[clang] [RISCV] Correct type lowering of struct of fixed-vector array in VLS (PR #147173)
https://github.com/4vtomat closed https://github.com/llvm/llvm-project/pull/147173 ___ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [RISCV] Correct type lowering of struct of fixed-vector array in VLS (PR #147173)
https://github.com/topperc approved this pull request. LGTM https://github.com/llvm/llvm-project/pull/147173 ___ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [RISCV] Correct type lowering of struct of fixed-vector array in VLS (PR #147173)
@@ -441,98 +441,74 @@ bool RISCVABIInfo::detectVLSCCEligibleStruct(QualType Ty,
unsigned ABIVLen,
// __attribute__((vector_size(64))) int d;
// }
//
- // Struct of 1 fixed-length vector is passed as a scalable vector.
- // Struct of >1 fixed-length vectors are passed as vector tuple.
- // Struct of 1 array of fixed-length vectors is passed as a scalable vector.
- // Otherwise, pass the struct indirectly.
-
- if (llvm::StructType *STy = dyn_cast(CGT.ConvertType(Ty)))
{
-unsigned NumElts = STy->getStructNumElements();
-if (NumElts > 8)
- return false;
+ // 1. Struct of 1 fixed-length vector is passed as a scalable vector.
+ // 2. Struct of >1 fixed-length vectors are passed as vector tuple.
+ // 3. Struct of an array with 1 element of fixed-length vectors is passed as
a
+ //scalable vector.
+ // 4. Struct of an array with >1 elements of fixed-length vectors is passed
as
+ //vector tuple.
+ // 5. Otherwise, pass the struct indirectly.
+
+ llvm::StructType *STy = dyn_cast(CGT.ConvertType(Ty));
+ if (!STy)
+return false;
-auto *FirstEltTy = STy->getElementType(0);
-if (!STy->containsHomogeneousTypes())
- return false;
+ unsigned NumElts = STy->getStructNumElements();
+ if (NumElts > 8)
+return false;
-// Check structure of fixed-length vectors and turn them into vector tuple
-// type if legal.
-if (auto *FixedVecTy = dyn_cast(FirstEltTy)) {
- if (NumElts == 1) {
-// Handle single fixed-length vector.
-VLSType = llvm::ScalableVectorType::get(
-FixedVecTy->getElementType(),
-llvm::divideCeil(FixedVecTy->getNumElements() *
- llvm::RISCV::RVVBitsPerBlock,
- ABIVLen));
-// Check registers needed <= 8.
-return llvm::divideCeil(
- FixedVecTy->getNumElements() *
- FixedVecTy->getElementType()->getScalarSizeInBits(),
- ABIVLen) <= 8;
- }
- // LMUL
- // = fixed-length vector size / ABIVLen
- // = 8 * I8EltCount / RVVBitsPerBlock
- // =>
- // I8EltCount
- // = (fixed-length vector size * RVVBitsPerBlock) / (ABIVLen * 8)
- unsigned I8EltCount = llvm::divideCeil(
- FixedVecTy->getNumElements() *
- FixedVecTy->getElementType()->getScalarSizeInBits() *
- llvm::RISCV::RVVBitsPerBlock,
- ABIVLen * 8);
- VLSType = llvm::TargetExtType::get(
- getVMContext(), "riscv.vector.tuple",
- llvm::ScalableVectorType::get(llvm::Type::getInt8Ty(getVMContext()),
-I8EltCount),
- NumElts);
- // Check registers needed <= 8.
- return NumElts *
- llvm::divideCeil(
- FixedVecTy->getNumElements() *
- FixedVecTy->getElementType()->getScalarSizeInBits(),
- ABIVLen) <=
- 8;
-}
+ auto *FirstEltTy = STy->getElementType(0);
+ if (!STy->containsHomogeneousTypes())
+return false;
-// If elements are not fixed-length vectors, it should be an array.
+ if (auto *ArrayTy = dyn_cast(FirstEltTy)) {
+// Only struct of single array is accepted
if (NumElts != 1)
return false;
+FirstEltTy = ArrayTy->getArrayElementType();
+NumElts = ArrayTy->getNumElements();
+ }
-// Check array of fixed-length vector and turn it into scalable vector type
-// if legal.
-if (auto *ArrTy = dyn_cast(FirstEltTy)) {
- unsigned NumArrElt = ArrTy->getNumElements();
- if (NumArrElt > 8)
-return false;
-
- auto *ArrEltTy =
dyn_cast(ArrTy->getElementType());
- if (!ArrEltTy)
-return false;
+ auto *FixedVecTy = dyn_cast(FirstEltTy);
+ if (!FixedVecTy)
+return false;
- // LMUL
- // = NumArrElt * fixed-length vector size / ABIVLen
- // = fixed-length vector elt size * ScalVecNumElts / RVVBitsPerBlock
- // =>
- // ScalVecNumElts
- // = (NumArrElt * fixed-length vector size * RVVBitsPerBlock) /
- // (ABIVLen * fixed-length vector elt size)
- // = NumArrElt * num fixed-length vector elt * RVVBitsPerBlock /
- // ABIVLen
- unsigned ScalVecNumElts = llvm::divideCeil(
- NumArrElt * ArrEltTy->getNumElements() *
llvm::RISCV::RVVBitsPerBlock,
- ABIVLen);
- VLSType = llvm::ScalableVectorType::get(ArrEltTy->getElementType(),
- ScalVecNumElts);
- // Check registers needed <= 8.
- return llvm::divideCeil(
- ScalVecNumElts *
- ArrEltTy->getElementType()->getScalarSizeInBits(),
- llvm::RISCV::RVVBitsPerBlock) <= 8;
-}
+ // Turn them into scalable vector type or vector tuple type if legal.
+ if (NumElts == 1) {
+// Handle single fixed-length vector.
+VLSType = llvm::ScalableVectorT
[clang] [RISCV] Correct type lowering of struct of fixed-vector array in VLS (PR #147173)
@@ -441,98 +441,74 @@ bool RISCVABIInfo::detectVLSCCEligibleStruct(QualType Ty,
unsigned ABIVLen,
// __attribute__((vector_size(64))) int d;
// }
//
- // Struct of 1 fixed-length vector is passed as a scalable vector.
- // Struct of >1 fixed-length vectors are passed as vector tuple.
- // Struct of 1 array of fixed-length vectors is passed as a scalable vector.
- // Otherwise, pass the struct indirectly.
-
- if (llvm::StructType *STy = dyn_cast(CGT.ConvertType(Ty)))
{
-unsigned NumElts = STy->getStructNumElements();
-if (NumElts > 8)
- return false;
+ // 1. Struct of 1 fixed-length vector is passed as a scalable vector.
+ // 2. Struct of >1 fixed-length vectors are passed as vector tuple.
+ // 3. Struct of an array with 1 element of fixed-length vectors is passed as
a
+ //scalable vector.
+ // 4. Struct of an array with >1 elements of fixed-length vectors is passed
as
+ //vector tuple.
+ // 5. Otherwise, pass the struct indirectly.
+
+ llvm::StructType *STy = dyn_cast(CGT.ConvertType(Ty));
+ if (!STy)
+return false;
-auto *FirstEltTy = STy->getElementType(0);
-if (!STy->containsHomogeneousTypes())
- return false;
+ unsigned NumElts = STy->getStructNumElements();
+ if (NumElts > 8)
+return false;
-// Check structure of fixed-length vectors and turn them into vector tuple
-// type if legal.
-if (auto *FixedVecTy = dyn_cast(FirstEltTy)) {
- if (NumElts == 1) {
-// Handle single fixed-length vector.
-VLSType = llvm::ScalableVectorType::get(
-FixedVecTy->getElementType(),
-llvm::divideCeil(FixedVecTy->getNumElements() *
- llvm::RISCV::RVVBitsPerBlock,
- ABIVLen));
-// Check registers needed <= 8.
-return llvm::divideCeil(
- FixedVecTy->getNumElements() *
- FixedVecTy->getElementType()->getScalarSizeInBits(),
- ABIVLen) <= 8;
- }
- // LMUL
- // = fixed-length vector size / ABIVLen
- // = 8 * I8EltCount / RVVBitsPerBlock
- // =>
- // I8EltCount
- // = (fixed-length vector size * RVVBitsPerBlock) / (ABIVLen * 8)
- unsigned I8EltCount = llvm::divideCeil(
- FixedVecTy->getNumElements() *
- FixedVecTy->getElementType()->getScalarSizeInBits() *
- llvm::RISCV::RVVBitsPerBlock,
- ABIVLen * 8);
- VLSType = llvm::TargetExtType::get(
- getVMContext(), "riscv.vector.tuple",
- llvm::ScalableVectorType::get(llvm::Type::getInt8Ty(getVMContext()),
-I8EltCount),
- NumElts);
- // Check registers needed <= 8.
- return NumElts *
- llvm::divideCeil(
- FixedVecTy->getNumElements() *
- FixedVecTy->getElementType()->getScalarSizeInBits(),
- ABIVLen) <=
- 8;
-}
+ auto *FirstEltTy = STy->getElementType(0);
+ if (!STy->containsHomogeneousTypes())
+return false;
-// If elements are not fixed-length vectors, it should be an array.
+ if (auto *ArrayTy = dyn_cast(FirstEltTy)) {
+// Only struct of single array is accepted
if (NumElts != 1)
return false;
+FirstEltTy = ArrayTy->getArrayElementType();
+NumElts = ArrayTy->getNumElements();
+ }
-// Check array of fixed-length vector and turn it into scalable vector type
-// if legal.
-if (auto *ArrTy = dyn_cast(FirstEltTy)) {
- unsigned NumArrElt = ArrTy->getNumElements();
- if (NumArrElt > 8)
-return false;
-
- auto *ArrEltTy =
dyn_cast(ArrTy->getElementType());
- if (!ArrEltTy)
-return false;
+ auto *FixedVecTy = dyn_cast(FirstEltTy);
+ if (!FixedVecTy)
+return false;
- // LMUL
- // = NumArrElt * fixed-length vector size / ABIVLen
- // = fixed-length vector elt size * ScalVecNumElts / RVVBitsPerBlock
- // =>
- // ScalVecNumElts
- // = (NumArrElt * fixed-length vector size * RVVBitsPerBlock) /
- // (ABIVLen * fixed-length vector elt size)
- // = NumArrElt * num fixed-length vector elt * RVVBitsPerBlock /
- // ABIVLen
- unsigned ScalVecNumElts = llvm::divideCeil(
- NumArrElt * ArrEltTy->getNumElements() *
llvm::RISCV::RVVBitsPerBlock,
- ABIVLen);
- VLSType = llvm::ScalableVectorType::get(ArrEltTy->getElementType(),
- ScalVecNumElts);
- // Check registers needed <= 8.
- return llvm::divideCeil(
- ScalVecNumElts *
- ArrEltTy->getElementType()->getScalarSizeInBits(),
- llvm::RISCV::RVVBitsPerBlock) <= 8;
-}
+ // Turn them into scalable vector type or vector tuple type if legal.
+ if (NumElts == 1) {
+// Handle single fixed-length vector.
+VLSType = llvm::ScalableVectorT
[clang] [RISCV] Correct type lowering of struct of fixed-vector array in VLS (PR #147173)
https://github.com/4vtomat updated
https://github.com/llvm/llvm-project/pull/147173
>From 1934543b7ec215312eebefd152f7c9151c2d0e54 Mon Sep 17 00:00:00 2001
From: Brandon Wu
Date: Sat, 5 Jul 2025 21:32:28 -0700
Subject: [PATCH 1/2] [RISCV] Correct type lowering of struct of fixed-vector
array in VLS
Currently, struct of fixed-vector array is flattened and lowered to
scalable vector. However only struct of 1-element-fixed-vector array
should be lowered that way, struct of fixed-vector array of length >1
should be lowered to vector tuple type.
https://github.com/riscv-non-isa/riscv-elf-psabi-doc/pull/418/files#diff-3a934f00cffdb3e509722753126a2cf6082a7648ab3b9ca8cbb0e84f8a6a12edR555-R558
---
clang/lib/CodeGen/Targets/RISCV.cpp | 144 --
.../RISCV/riscv-vector-callingconv-llvm-ir.c | 8 +-
.../riscv-vector-callingconv-llvm-ir.cpp | 8 +-
3 files changed, 68 insertions(+), 92 deletions(-)
diff --git a/clang/lib/CodeGen/Targets/RISCV.cpp
b/clang/lib/CodeGen/Targets/RISCV.cpp
index cc3d487da83b5..e1603d3095a04 100644
--- a/clang/lib/CodeGen/Targets/RISCV.cpp
+++ b/clang/lib/CodeGen/Targets/RISCV.cpp
@@ -441,98 +441,74 @@ bool RISCVABIInfo::detectVLSCCEligibleStruct(QualType Ty,
unsigned ABIVLen,
// __attribute__((vector_size(64))) int d;
// }
//
- // Struct of 1 fixed-length vector is passed as a scalable vector.
- // Struct of >1 fixed-length vectors are passed as vector tuple.
- // Struct of 1 array of fixed-length vectors is passed as a scalable vector.
- // Otherwise, pass the struct indirectly.
-
- if (llvm::StructType *STy = dyn_cast(CGT.ConvertType(Ty)))
{
-unsigned NumElts = STy->getStructNumElements();
-if (NumElts > 8)
- return false;
+ // 1. Struct of 1 fixed-length vector is passed as a scalable vector.
+ // 2. Struct of >1 fixed-length vectors are passed as vector tuple.
+ // 3. Struct of an array with 1 element of fixed-length vectors is passed as
a
+ //scalable vector.
+ // 4. Struct of an array with >1 elements of fixed-length vectors is passed
as
+ //vector tuple.
+ // 5. Otherwise, pass the struct indirectly.
+
+ llvm::StructType *STy = dyn_cast(CGT.ConvertType(Ty));
+ if (!STy)
+return false;
-auto *FirstEltTy = STy->getElementType(0);
-if (!STy->containsHomogeneousTypes())
- return false;
+ unsigned NumElts = STy->getStructNumElements();
+ if (NumElts > 8)
+return false;
-// Check structure of fixed-length vectors and turn them into vector tuple
-// type if legal.
-if (auto *FixedVecTy = dyn_cast(FirstEltTy)) {
- if (NumElts == 1) {
-// Handle single fixed-length vector.
-VLSType = llvm::ScalableVectorType::get(
-FixedVecTy->getElementType(),
-llvm::divideCeil(FixedVecTy->getNumElements() *
- llvm::RISCV::RVVBitsPerBlock,
- ABIVLen));
-// Check registers needed <= 8.
-return llvm::divideCeil(
- FixedVecTy->getNumElements() *
- FixedVecTy->getElementType()->getScalarSizeInBits(),
- ABIVLen) <= 8;
- }
- // LMUL
- // = fixed-length vector size / ABIVLen
- // = 8 * I8EltCount / RVVBitsPerBlock
- // =>
- // I8EltCount
- // = (fixed-length vector size * RVVBitsPerBlock) / (ABIVLen * 8)
- unsigned I8EltCount = llvm::divideCeil(
- FixedVecTy->getNumElements() *
- FixedVecTy->getElementType()->getScalarSizeInBits() *
- llvm::RISCV::RVVBitsPerBlock,
- ABIVLen * 8);
- VLSType = llvm::TargetExtType::get(
- getVMContext(), "riscv.vector.tuple",
- llvm::ScalableVectorType::get(llvm::Type::getInt8Ty(getVMContext()),
-I8EltCount),
- NumElts);
- // Check registers needed <= 8.
- return NumElts *
- llvm::divideCeil(
- FixedVecTy->getNumElements() *
- FixedVecTy->getElementType()->getScalarSizeInBits(),
- ABIVLen) <=
- 8;
-}
+ auto *FirstEltTy = STy->getElementType(0);
+ if (!STy->containsHomogeneousTypes())
+return false;
-// If elements are not fixed-length vectors, it should be an array.
+ if (auto *ArrayTy = dyn_cast(FirstEltTy)) {
+// Only struct of single array is accepted
if (NumElts != 1)
return false;
+FirstEltTy = ArrayTy->getArrayElementType();
+NumElts = ArrayTy->getNumElements();
+ }
-// Check array of fixed-length vector and turn it into scalable vector type
-// if legal.
-if (auto *ArrTy = dyn_cast(FirstEltTy)) {
- unsigned NumArrElt = ArrTy->getNumElements();
- if (NumArrElt > 8)
-return false;
-
- auto *ArrEltTy =
dyn_cast(ArrTy->getElementType());
- if (!ArrEltTy)
-return false;
+ auto *FixedVecTy = dyn_cast(FirstEltTy);
+ if (!FixedVecT
[clang] [RISCV] Correct type lowering of struct of fixed-vector array in VLS (PR #147173)
llvmbot wrote:
@llvm/pr-subscribers-clang
Author: Brandon Wu (4vtomat)
Changes
Currently, struct of fixed-vector array is flattened and lowered to
scalable vector. However only struct of 1-element-fixed-vector array
should be lowered that way, struct of fixed-vector array of length >1
should be lowered to vector tuple type.
https://github.com/riscv-non-isa/riscv-elf-psabi-doc/pull/418/files#diff-3a934f00cffdb3e509722753126a2cf6082a7648ab3b9ca8cbb0e84f8a6a12edR555-R558
---
Full diff: https://github.com/llvm/llvm-project/pull/147173.diff
3 Files Affected:
- (modified) clang/lib/CodeGen/Targets/RISCV.cpp (+60-84)
- (modified) clang/test/CodeGen/RISCV/riscv-vector-callingconv-llvm-ir.c (+4-4)
- (modified) clang/test/CodeGen/RISCV/riscv-vector-callingconv-llvm-ir.cpp
(+4-4)
``diff
diff --git a/clang/lib/CodeGen/Targets/RISCV.cpp
b/clang/lib/CodeGen/Targets/RISCV.cpp
index cc3d487da83b5..e1603d3095a04 100644
--- a/clang/lib/CodeGen/Targets/RISCV.cpp
+++ b/clang/lib/CodeGen/Targets/RISCV.cpp
@@ -441,98 +441,74 @@ bool RISCVABIInfo::detectVLSCCEligibleStruct(QualType Ty,
unsigned ABIVLen,
// __attribute__((vector_size(64))) int d;
// }
//
- // Struct of 1 fixed-length vector is passed as a scalable vector.
- // Struct of >1 fixed-length vectors are passed as vector tuple.
- // Struct of 1 array of fixed-length vectors is passed as a scalable vector.
- // Otherwise, pass the struct indirectly.
-
- if (llvm::StructType *STy = dyn_cast(CGT.ConvertType(Ty)))
{
-unsigned NumElts = STy->getStructNumElements();
-if (NumElts > 8)
- return false;
+ // 1. Struct of 1 fixed-length vector is passed as a scalable vector.
+ // 2. Struct of >1 fixed-length vectors are passed as vector tuple.
+ // 3. Struct of an array with 1 element of fixed-length vectors is passed as
a
+ //scalable vector.
+ // 4. Struct of an array with >1 elements of fixed-length vectors is passed
as
+ //vector tuple.
+ // 5. Otherwise, pass the struct indirectly.
+
+ llvm::StructType *STy = dyn_cast(CGT.ConvertType(Ty));
+ if (!STy)
+return false;
-auto *FirstEltTy = STy->getElementType(0);
-if (!STy->containsHomogeneousTypes())
- return false;
+ unsigned NumElts = STy->getStructNumElements();
+ if (NumElts > 8)
+return false;
-// Check structure of fixed-length vectors and turn them into vector tuple
-// type if legal.
-if (auto *FixedVecTy = dyn_cast(FirstEltTy)) {
- if (NumElts == 1) {
-// Handle single fixed-length vector.
-VLSType = llvm::ScalableVectorType::get(
-FixedVecTy->getElementType(),
-llvm::divideCeil(FixedVecTy->getNumElements() *
- llvm::RISCV::RVVBitsPerBlock,
- ABIVLen));
-// Check registers needed <= 8.
-return llvm::divideCeil(
- FixedVecTy->getNumElements() *
- FixedVecTy->getElementType()->getScalarSizeInBits(),
- ABIVLen) <= 8;
- }
- // LMUL
- // = fixed-length vector size / ABIVLen
- // = 8 * I8EltCount / RVVBitsPerBlock
- // =>
- // I8EltCount
- // = (fixed-length vector size * RVVBitsPerBlock) / (ABIVLen * 8)
- unsigned I8EltCount = llvm::divideCeil(
- FixedVecTy->getNumElements() *
- FixedVecTy->getElementType()->getScalarSizeInBits() *
- llvm::RISCV::RVVBitsPerBlock,
- ABIVLen * 8);
- VLSType = llvm::TargetExtType::get(
- getVMContext(), "riscv.vector.tuple",
- llvm::ScalableVectorType::get(llvm::Type::getInt8Ty(getVMContext()),
-I8EltCount),
- NumElts);
- // Check registers needed <= 8.
- return NumElts *
- llvm::divideCeil(
- FixedVecTy->getNumElements() *
- FixedVecTy->getElementType()->getScalarSizeInBits(),
- ABIVLen) <=
- 8;
-}
+ auto *FirstEltTy = STy->getElementType(0);
+ if (!STy->containsHomogeneousTypes())
+return false;
-// If elements are not fixed-length vectors, it should be an array.
+ if (auto *ArrayTy = dyn_cast(FirstEltTy)) {
+// Only struct of single array is accepted
if (NumElts != 1)
return false;
+FirstEltTy = ArrayTy->getArrayElementType();
+NumElts = ArrayTy->getNumElements();
+ }
-// Check array of fixed-length vector and turn it into scalable vector type
-// if legal.
-if (auto *ArrTy = dyn_cast(FirstEltTy)) {
- unsigned NumArrElt = ArrTy->getNumElements();
- if (NumArrElt > 8)
-return false;
-
- auto *ArrEltTy =
dyn_cast(ArrTy->getElementType());
- if (!ArrEltTy)
-return false;
+ auto *FixedVecTy = dyn_cast(FirstEltTy);
+ if (!FixedVecTy)
+return false;
- // LMUL
- // = NumArrElt * fixed-length vector size / ABIVLen
- // = fixed-length vec
[clang] [RISCV] Correct type lowering of struct of fixed-vector array in VLS (PR #147173)
llvmbot wrote:
@llvm/pr-subscribers-backend-risc-v
Author: Brandon Wu (4vtomat)
Changes
Currently, struct of fixed-vector array is flattened and lowered to
scalable vector. However only struct of 1-element-fixed-vector array
should be lowered that way, struct of fixed-vector array of length >1
should be lowered to vector tuple type.
https://github.com/riscv-non-isa/riscv-elf-psabi-doc/pull/418/files#diff-3a934f00cffdb3e509722753126a2cf6082a7648ab3b9ca8cbb0e84f8a6a12edR555-R558
---
Full diff: https://github.com/llvm/llvm-project/pull/147173.diff
3 Files Affected:
- (modified) clang/lib/CodeGen/Targets/RISCV.cpp (+60-84)
- (modified) clang/test/CodeGen/RISCV/riscv-vector-callingconv-llvm-ir.c (+4-4)
- (modified) clang/test/CodeGen/RISCV/riscv-vector-callingconv-llvm-ir.cpp
(+4-4)
``diff
diff --git a/clang/lib/CodeGen/Targets/RISCV.cpp
b/clang/lib/CodeGen/Targets/RISCV.cpp
index cc3d487da83b5..e1603d3095a04 100644
--- a/clang/lib/CodeGen/Targets/RISCV.cpp
+++ b/clang/lib/CodeGen/Targets/RISCV.cpp
@@ -441,98 +441,74 @@ bool RISCVABIInfo::detectVLSCCEligibleStruct(QualType Ty,
unsigned ABIVLen,
// __attribute__((vector_size(64))) int d;
// }
//
- // Struct of 1 fixed-length vector is passed as a scalable vector.
- // Struct of >1 fixed-length vectors are passed as vector tuple.
- // Struct of 1 array of fixed-length vectors is passed as a scalable vector.
- // Otherwise, pass the struct indirectly.
-
- if (llvm::StructType *STy = dyn_cast(CGT.ConvertType(Ty)))
{
-unsigned NumElts = STy->getStructNumElements();
-if (NumElts > 8)
- return false;
+ // 1. Struct of 1 fixed-length vector is passed as a scalable vector.
+ // 2. Struct of >1 fixed-length vectors are passed as vector tuple.
+ // 3. Struct of an array with 1 element of fixed-length vectors is passed as
a
+ //scalable vector.
+ // 4. Struct of an array with >1 elements of fixed-length vectors is passed
as
+ //vector tuple.
+ // 5. Otherwise, pass the struct indirectly.
+
+ llvm::StructType *STy = dyn_cast(CGT.ConvertType(Ty));
+ if (!STy)
+return false;
-auto *FirstEltTy = STy->getElementType(0);
-if (!STy->containsHomogeneousTypes())
- return false;
+ unsigned NumElts = STy->getStructNumElements();
+ if (NumElts > 8)
+return false;
-// Check structure of fixed-length vectors and turn them into vector tuple
-// type if legal.
-if (auto *FixedVecTy = dyn_cast(FirstEltTy)) {
- if (NumElts == 1) {
-// Handle single fixed-length vector.
-VLSType = llvm::ScalableVectorType::get(
-FixedVecTy->getElementType(),
-llvm::divideCeil(FixedVecTy->getNumElements() *
- llvm::RISCV::RVVBitsPerBlock,
- ABIVLen));
-// Check registers needed <= 8.
-return llvm::divideCeil(
- FixedVecTy->getNumElements() *
- FixedVecTy->getElementType()->getScalarSizeInBits(),
- ABIVLen) <= 8;
- }
- // LMUL
- // = fixed-length vector size / ABIVLen
- // = 8 * I8EltCount / RVVBitsPerBlock
- // =>
- // I8EltCount
- // = (fixed-length vector size * RVVBitsPerBlock) / (ABIVLen * 8)
- unsigned I8EltCount = llvm::divideCeil(
- FixedVecTy->getNumElements() *
- FixedVecTy->getElementType()->getScalarSizeInBits() *
- llvm::RISCV::RVVBitsPerBlock,
- ABIVLen * 8);
- VLSType = llvm::TargetExtType::get(
- getVMContext(), "riscv.vector.tuple",
- llvm::ScalableVectorType::get(llvm::Type::getInt8Ty(getVMContext()),
-I8EltCount),
- NumElts);
- // Check registers needed <= 8.
- return NumElts *
- llvm::divideCeil(
- FixedVecTy->getNumElements() *
- FixedVecTy->getElementType()->getScalarSizeInBits(),
- ABIVLen) <=
- 8;
-}
+ auto *FirstEltTy = STy->getElementType(0);
+ if (!STy->containsHomogeneousTypes())
+return false;
-// If elements are not fixed-length vectors, it should be an array.
+ if (auto *ArrayTy = dyn_cast(FirstEltTy)) {
+// Only struct of single array is accepted
if (NumElts != 1)
return false;
+FirstEltTy = ArrayTy->getArrayElementType();
+NumElts = ArrayTy->getNumElements();
+ }
-// Check array of fixed-length vector and turn it into scalable vector type
-// if legal.
-if (auto *ArrTy = dyn_cast(FirstEltTy)) {
- unsigned NumArrElt = ArrTy->getNumElements();
- if (NumArrElt > 8)
-return false;
-
- auto *ArrEltTy =
dyn_cast(ArrTy->getElementType());
- if (!ArrEltTy)
-return false;
+ auto *FixedVecTy = dyn_cast(FirstEltTy);
+ if (!FixedVecTy)
+return false;
- // LMUL
- // = NumArrElt * fixed-length vector size / ABIVLen
- // = fixed-l
[clang] [RISCV] Correct type lowering of struct of fixed-vector array in VLS (PR #147173)
https://github.com/4vtomat created
https://github.com/llvm/llvm-project/pull/147173
Currently, struct of fixed-vector array is flattened and lowered to
scalable vector. However only struct of 1-element-fixed-vector array
should be lowered that way, struct of fixed-vector array of length >1
should be lowered to vector tuple type.
https://github.com/riscv-non-isa/riscv-elf-psabi-doc/pull/418/files#diff-3a934f00cffdb3e509722753126a2cf6082a7648ab3b9ca8cbb0e84f8a6a12edR555-R558
>From 1934543b7ec215312eebefd152f7c9151c2d0e54 Mon Sep 17 00:00:00 2001
From: Brandon Wu
Date: Sat, 5 Jul 2025 21:32:28 -0700
Subject: [PATCH] [RISCV] Correct type lowering of struct of fixed-vector array
in VLS
Currently, struct of fixed-vector array is flattened and lowered to
scalable vector. However only struct of 1-element-fixed-vector array
should be lowered that way, struct of fixed-vector array of length >1
should be lowered to vector tuple type.
https://github.com/riscv-non-isa/riscv-elf-psabi-doc/pull/418/files#diff-3a934f00cffdb3e509722753126a2cf6082a7648ab3b9ca8cbb0e84f8a6a12edR555-R558
---
clang/lib/CodeGen/Targets/RISCV.cpp | 144 --
.../RISCV/riscv-vector-callingconv-llvm-ir.c | 8 +-
.../riscv-vector-callingconv-llvm-ir.cpp | 8 +-
3 files changed, 68 insertions(+), 92 deletions(-)
diff --git a/clang/lib/CodeGen/Targets/RISCV.cpp
b/clang/lib/CodeGen/Targets/RISCV.cpp
index cc3d487da83b5..e1603d3095a04 100644
--- a/clang/lib/CodeGen/Targets/RISCV.cpp
+++ b/clang/lib/CodeGen/Targets/RISCV.cpp
@@ -441,98 +441,74 @@ bool RISCVABIInfo::detectVLSCCEligibleStruct(QualType Ty,
unsigned ABIVLen,
// __attribute__((vector_size(64))) int d;
// }
//
- // Struct of 1 fixed-length vector is passed as a scalable vector.
- // Struct of >1 fixed-length vectors are passed as vector tuple.
- // Struct of 1 array of fixed-length vectors is passed as a scalable vector.
- // Otherwise, pass the struct indirectly.
-
- if (llvm::StructType *STy = dyn_cast(CGT.ConvertType(Ty)))
{
-unsigned NumElts = STy->getStructNumElements();
-if (NumElts > 8)
- return false;
+ // 1. Struct of 1 fixed-length vector is passed as a scalable vector.
+ // 2. Struct of >1 fixed-length vectors are passed as vector tuple.
+ // 3. Struct of an array with 1 element of fixed-length vectors is passed as
a
+ //scalable vector.
+ // 4. Struct of an array with >1 elements of fixed-length vectors is passed
as
+ //vector tuple.
+ // 5. Otherwise, pass the struct indirectly.
+
+ llvm::StructType *STy = dyn_cast(CGT.ConvertType(Ty));
+ if (!STy)
+return false;
-auto *FirstEltTy = STy->getElementType(0);
-if (!STy->containsHomogeneousTypes())
- return false;
+ unsigned NumElts = STy->getStructNumElements();
+ if (NumElts > 8)
+return false;
-// Check structure of fixed-length vectors and turn them into vector tuple
-// type if legal.
-if (auto *FixedVecTy = dyn_cast(FirstEltTy)) {
- if (NumElts == 1) {
-// Handle single fixed-length vector.
-VLSType = llvm::ScalableVectorType::get(
-FixedVecTy->getElementType(),
-llvm::divideCeil(FixedVecTy->getNumElements() *
- llvm::RISCV::RVVBitsPerBlock,
- ABIVLen));
-// Check registers needed <= 8.
-return llvm::divideCeil(
- FixedVecTy->getNumElements() *
- FixedVecTy->getElementType()->getScalarSizeInBits(),
- ABIVLen) <= 8;
- }
- // LMUL
- // = fixed-length vector size / ABIVLen
- // = 8 * I8EltCount / RVVBitsPerBlock
- // =>
- // I8EltCount
- // = (fixed-length vector size * RVVBitsPerBlock) / (ABIVLen * 8)
- unsigned I8EltCount = llvm::divideCeil(
- FixedVecTy->getNumElements() *
- FixedVecTy->getElementType()->getScalarSizeInBits() *
- llvm::RISCV::RVVBitsPerBlock,
- ABIVLen * 8);
- VLSType = llvm::TargetExtType::get(
- getVMContext(), "riscv.vector.tuple",
- llvm::ScalableVectorType::get(llvm::Type::getInt8Ty(getVMContext()),
-I8EltCount),
- NumElts);
- // Check registers needed <= 8.
- return NumElts *
- llvm::divideCeil(
- FixedVecTy->getNumElements() *
- FixedVecTy->getElementType()->getScalarSizeInBits(),
- ABIVLen) <=
- 8;
-}
+ auto *FirstEltTy = STy->getElementType(0);
+ if (!STy->containsHomogeneousTypes())
+return false;
-// If elements are not fixed-length vectors, it should be an array.
+ if (auto *ArrayTy = dyn_cast(FirstEltTy)) {
+// Only struct of single array is accepted
if (NumElts != 1)
return false;
+FirstEltTy = ArrayTy->getArrayElementType();
+NumElts = ArrayTy->getNumElements();
+ }
-// Check array of f
