[CodeGen][va_args] Correct Vector Struct va-arg 'in_reg' code gen
When trying to track down a different bug, we discovered
that calling __builtin_va_arg on a vec3f type caused
the SROA pass to issue a warning that there was an illegal
access.
Further research showed that the vec3f type is
alloca'ed as size '12', but the _builtin_va_arg code
on x86_64 was always loading this out of registers as
{double, double}. Thus, the 2nd store into the vec3f
was storing in bytes 12-15!
This patch alters the original implementation which always
assumed {double, double} to use the actual coerced type
instead, so the LLVM-IR generated is a load/GEP/store of
a <2 x float> and a float, rather than a double and a double.
Tests were added for all combinations I could think of that
would fit in 2 FP registers, and all work exactly as expected.
Differential Revision: https://reviews.llvm.org/D42811
llvm-svn: 324098
diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
index 8641d87..f523096 100644
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -3790,17 +3790,18 @@
Address RegAddrHi =
CGF.Builder.CreateConstInBoundsByteGEP(RegAddrLo,
CharUnits::fromQuantity(16));
- llvm::Type *DoubleTy = CGF.DoubleTy;
- llvm::StructType *ST = llvm::StructType::get(DoubleTy, DoubleTy);
+ llvm::Type *ST = AI.canHaveCoerceToType()
+ ? AI.getCoerceToType()
+ : llvm::StructType::get(CGF.DoubleTy, CGF.DoubleTy);
llvm::Value *V;
Address Tmp = CGF.CreateMemTemp(Ty);
Tmp = CGF.Builder.CreateElementBitCast(Tmp, ST);
- V = CGF.Builder.CreateLoad(
- CGF.Builder.CreateElementBitCast(RegAddrLo, DoubleTy));
+ V = CGF.Builder.CreateLoad(CGF.Builder.CreateElementBitCast(
+ RegAddrLo, ST->getStructElementType(0)));
CGF.Builder.CreateStore(V,
CGF.Builder.CreateStructGEP(Tmp, 0, CharUnits::Zero()));
- V = CGF.Builder.CreateLoad(
- CGF.Builder.CreateElementBitCast(RegAddrHi, DoubleTy));
+ V = CGF.Builder.CreateLoad(CGF.Builder.CreateElementBitCast(
+ RegAddrHi, ST->getStructElementType(1)));
CGF.Builder.CreateStore(V,
CGF.Builder.CreateStructGEP(Tmp, 1, CharUnits::fromQuantity(8)));