[clang] [HLSL] Use ExtVector for firstbit intrinsics (PR #142679)

[Ashley Coleman via cfe-commits]

https://github.com/V-FEXrt updated 
https://github.com/llvm/llvm-project/pull/142679

>From 7a294ecd713cf6c4fb095a1b3f6f6793d50657a8 Mon Sep 17 00:00:00 2001
From: Ashley Coleman <ascole...@microsoft.com>
Date: Tue, 3 Jun 2025 16:05:24 -0600
Subject: [PATCH 1/2] [HLSL] Use ExtVector for firstbit intrinsics

---
 clang/lib/Sema/SemaHLSL.cpp                       | 3 +--
 clang/test/CodeGenHLSL/builtins/firstbithigh.hlsl | 8 ++++++++
 clang/test/CodeGenHLSL/builtins/firstbitlow.hlsl  | 8 ++++++++
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/clang/lib/Sema/SemaHLSL.cpp b/clang/lib/Sema/SemaHLSL.cpp
index 43db85594de3d..b923d1204d8d6 100644
--- a/clang/lib/Sema/SemaHLSL.cpp
+++ b/clang/lib/Sema/SemaHLSL.cpp
@@ -2485,8 +2485,7 @@ bool SemaHLSL::CheckBuiltinFunctionCall(unsigned 
BuiltinID, CallExpr *TheCall) {
 
     if (auto *VecTy = EltTy->getAs<VectorType>()) {
       EltTy = VecTy->getElementType();
-      ResTy = SemaRef.Context.getVectorType(ResTy, VecTy->getNumElements(),
-                                            VecTy->getVectorKind());
+      ResTy = SemaRef.Context.getExtVectorType(ResTy, VecTy->getNumElements());
     }
 
     if (!EltTy->isIntegerType()) {
diff --git a/clang/test/CodeGenHLSL/builtins/firstbithigh.hlsl 
b/clang/test/CodeGenHLSL/builtins/firstbithigh.hlsl
index debf6b6d3e3f5..a71b1878f8b55 100644
--- a/clang/test/CodeGenHLSL/builtins/firstbithigh.hlsl
+++ b/clang/test/CodeGenHLSL/builtins/firstbithigh.hlsl
@@ -151,3 +151,11 @@ uint3 test_firstbithigh_long3(int64_t3 p0) {
 uint4 test_firstbithigh_long4(int64_t4 p0) {
   return firstbithigh(p0);
 }
+
+// CHECK-LABEL: test_firstbithigh_upcast
+// CHECK: [[FBH:%.*]] = call <4 x i32> @llvm.[[TARGET]].firstbituhigh.v4i32(<4 
x i32> %{{.*}})
+// CHECK: [[CONV:%.*]] = zext <4 x i32> [[FBH]] to <4 x i64>
+// CHECK: ret <4 x i64> [[CONV]]
+uint64_t4 test_firstbithigh_upcast(uint4 p0) {
+  return firstbithigh(p0);
+}
diff --git a/clang/test/CodeGenHLSL/builtins/firstbitlow.hlsl 
b/clang/test/CodeGenHLSL/builtins/firstbitlow.hlsl
index 5d490fabc5bc8..007db0c9c2ad5 100644
--- a/clang/test/CodeGenHLSL/builtins/firstbitlow.hlsl
+++ b/clang/test/CodeGenHLSL/builtins/firstbitlow.hlsl
@@ -151,3 +151,11 @@ uint3 test_firstbitlow_long3(int64_t3 p0) {
 uint4 test_firstbitlow_long4(int64_t4 p0) {
   return firstbitlow(p0);
 }
+
+// CHECK-LABEL: test_firstbitlow_upcast
+// CHECK: [[FBL:%.*]] = call <4 x i32> @llvm.[[TARGET]].firstbitlow.v4i32(<4 x 
i32> %{{.*}})
+// CHECK: [[CONV:%.*]] = zext <4 x i32> [[FBL]] to <4 x i64>
+// CHECK: ret <4 x i64> [[CONV]]
+uint64_t4 test_firstbitlow_upcast(uint4 p0) {
+  return firstbitlow(p0);
+}

>From 9ba8e0fb9ed92ac585591c908f2510c15e50777f Mon Sep 17 00:00:00 2001
From: Ashley Coleman <ascole...@microsoft.com>
Date: Wed, 4 Jun 2025 10:22:07 -0600
Subject: [PATCH 2/2] Address Comments

---
 clang/lib/Sema/SemaHLSL.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/clang/lib/Sema/SemaHLSL.cpp b/clang/lib/Sema/SemaHLSL.cpp
index b923d1204d8d6..3ca11b17f708a 100644
--- a/clang/lib/Sema/SemaHLSL.cpp
+++ b/clang/lib/Sema/SemaHLSL.cpp
@@ -2171,8 +2171,9 @@ static void SetElementTypeAsReturnType(Sema *S, CallExpr 
*TheCall,
                                        QualType ReturnType) {
   auto *VecTyA = TheCall->getArg(0)->getType()->getAs<VectorType>();
   if (VecTyA)
-    ReturnType = S->Context.getVectorType(ReturnType, VecTyA->getNumElements(),
-                                          VectorKind::Generic);
+    ReturnType =
+        S->Context.getExtVectorType(ReturnType, VecTyA->getNumElements());
+
   TheCall->setType(ReturnType);
 }
 

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