Author: Nikita Popov Date: 2025-12-16T09:48:28+01:00 New Revision: af3f2da253bb7a2edcddd67467023f3531700ae4
URL: https://github.com/llvm/llvm-project/commit/af3f2da253bb7a2edcddd67467023f3531700ae4 DIFF: https://github.com/llvm/llvm-project/commit/af3f2da253bb7a2edcddd67467023f3531700ae4.diff LOG: [CGExprScalar] Fix inc/dec of vector larger than 64-bit (#172301) Use getSigned() to create the 1 or -1 constant, so it gets properly sign extended. This miscompile was found while working on https://github.com/llvm/llvm-project/pull/171456. Added: Modified: clang/lib/CodeGen/CGExprScalar.cpp clang/test/CodeGen/SystemZ/zvector.c Removed: ################################################################################ diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp index 769bc37b0e131..9b6497fca829a 100644 --- a/clang/lib/CodeGen/CGExprScalar.cpp +++ b/clang/lib/CodeGen/CGExprScalar.cpp @@ -3335,7 +3335,7 @@ ScalarExprEmitter::EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV, // Vector increment/decrement. } else if (type->isVectorType()) { if (type->hasIntegerRepresentation()) { - llvm::Value *amt = llvm::ConstantInt::get(value->getType(), amount); + llvm::Value *amt = llvm::ConstantInt::getSigned(value->getType(), amount); value = Builder.CreateAdd(value, amt, isInc ? "inc" : "dec"); } else { diff --git a/clang/test/CodeGen/SystemZ/zvector.c b/clang/test/CodeGen/SystemZ/zvector.c index a0b654d9acc9a..35bee8d41df61 100644 --- a/clang/test/CodeGen/SystemZ/zvector.c +++ b/clang/test/CodeGen/SystemZ/zvector.c @@ -298,10 +298,10 @@ void test_postinc(void) { // CHECK-NEXT: [[DEC7:%.*]] = add <2 x i64> [[TMP7]], splat (i64 -1) // CHECK-NEXT: store volatile <2 x i64> [[DEC7]], ptr @ul2, align 8 // CHECK-NEXT: [[TMP8:%.*]] = load volatile <1 x i128>, ptr @slll2, align 8 -// CHECK-NEXT: [[DEC8:%.*]] = add <1 x i128> [[TMP8]], splat (i128 18446744073709551615) +// CHECK-NEXT: [[DEC8:%.*]] = add <1 x i128> [[TMP8]], splat (i128 -1) // CHECK-NEXT: store volatile <1 x i128> [[DEC8]], ptr @slll2, align 8 // CHECK-NEXT: [[TMP9:%.*]] = load volatile <1 x i128>, ptr @ulll2, align 8 -// CHECK-NEXT: [[DEC9:%.*]] = add <1 x i128> [[TMP9]], splat (i128 18446744073709551615) +// CHECK-NEXT: [[DEC9:%.*]] = add <1 x i128> [[TMP9]], splat (i128 -1) // CHECK-NEXT: store volatile <1 x i128> [[DEC9]], ptr @ulll2, align 8 // CHECK-NEXT: [[TMP10:%.*]] = load volatile <2 x double>, ptr @fd2, align 8 // CHECK-NEXT: [[DEC10:%.*]] = fadd <2 x double> [[TMP10]], splat (double -1.000000e+00) @@ -356,10 +356,10 @@ void test_predec(void) { // CHECK-NEXT: [[DEC7:%.*]] = add <2 x i64> [[TMP7]], splat (i64 -1) // CHECK-NEXT: store volatile <2 x i64> [[DEC7]], ptr @ul2, align 8 // CHECK-NEXT: [[TMP8:%.*]] = load volatile <1 x i128>, ptr @slll2, align 8 -// CHECK-NEXT: [[DEC8:%.*]] = add <1 x i128> [[TMP8]], splat (i128 18446744073709551615) +// CHECK-NEXT: [[DEC8:%.*]] = add <1 x i128> [[TMP8]], splat (i128 -1) // CHECK-NEXT: store volatile <1 x i128> [[DEC8]], ptr @slll2, align 8 // CHECK-NEXT: [[TMP9:%.*]] = load volatile <1 x i128>, ptr @ulll2, align 8 -// CHECK-NEXT: [[DEC9:%.*]] = add <1 x i128> [[TMP9]], splat (i128 18446744073709551615) +// CHECK-NEXT: [[DEC9:%.*]] = add <1 x i128> [[TMP9]], splat (i128 -1) // CHECK-NEXT: store volatile <1 x i128> [[DEC9]], ptr @ulll2, align 8 // CHECK-NEXT: [[TMP10:%.*]] = load volatile <2 x double>, ptr @fd2, align 8 // CHECK-NEXT: [[DEC10:%.*]] = fadd <2 x double> [[TMP10]], splat (double -1.000000e+00) _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
