From a6399a519d4d89602ecf918b3d6841601095a648 Mon Sep 17 00:00:00 2001 From: Chandler Carruth Date: Wed, 10 Oct 2012 11:29:08 +0000 Subject: [PATCH] Apply the same fundamental fix for PR14048 as was applied for PR11905. The issue arises when coercing to/from types of different sizes. We need to be certain that the allocation on either end has sufficient room for the coerced type. When it doesn't, we need to make room, copy across, and then proceed. PR11905 handled the case of storing function arguments back into allocas in the function prolog, this patch handles the case of setting up the function arguments in a call expression. This is actually significantly simpler than the fix for PR11905. It ends up being a trivial change to create a temporary alloca when the source is too small and memcpy across. This should preserve the compile-time fast-isel benefits of doing gep+load sequences and avoiding FCAs. Reviewed by Benjamin and Evgeniy (who fixed PR11905). llvm-svn: 165615 --- clang/lib/CodeGen/CGCall.cpp | 21 +++++++++++++++++++-- clang/test/CodeGen/arm-arguments.c | 13 +++++++++++++ 2 files changed, 32 insertions(+), 2 deletions(-) diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp index 562c17d..e8d99e2 100644 --- a/clang/lib/CodeGen/CGCall.cpp +++ b/clang/lib/CodeGen/CGCall.cpp @@ -2073,8 +2073,25 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo, // and the optimizer generally likes scalar values better than FCAs. if (llvm::StructType *STy = dyn_cast(ArgInfo.getCoerceToType())) { - SrcPtr = Builder.CreateBitCast(SrcPtr, - llvm::PointerType::getUnqual(STy)); + llvm::Type *SrcTy = + cast(SrcPtr->getType())->getElementType(); + uint64_t SrcSize = CGM.getDataLayout().getTypeAllocSize(SrcTy); + uint64_t DstSize = CGM.getDataLayout().getTypeAllocSize(STy); + + // If the source type is smaller than the destination type of the + // coerce-to logic, copy the source value into a temp alloca the size + // of the destination type to allow loading all of it. The bits past + // the source value are left undef. + if (SrcSize < DstSize) { + llvm::AllocaInst *TempAlloca + = CreateTempAlloca(STy, SrcPtr->getName() + ".coerce"); + Builder.CreateMemCpy(TempAlloca, SrcPtr, SrcSize, 0); + SrcPtr = TempAlloca; + } else { + SrcPtr = Builder.CreateBitCast(SrcPtr, + llvm::PointerType::getUnqual(STy)); + } + for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) { llvm::Value *EltPtr = Builder.CreateConstGEP2_32(SrcPtr, 0, i); llvm::LoadInst *LI = Builder.CreateLoad(EltPtr); diff --git a/clang/test/CodeGen/arm-arguments.c b/clang/test/CodeGen/arm-arguments.c index 2ec729e..8aa33f6 100644 --- a/clang/test/CodeGen/arm-arguments.c +++ b/clang/test/CodeGen/arm-arguments.c @@ -178,3 +178,16 @@ struct s33 { char buf[32*32]; }; void f33(struct s33 s) { } // APCS-GNU: define void @f33(%struct.s33* byval %s) // AAPCS: define arm_aapcscc void @f33(%struct.s33* byval %s) + +// PR14048 +struct s34 { char c; }; +void f34(struct s34 s); +void g34(struct s34 *s) { f34(*s); } +// APCS-GNU: @g34(%struct.s34* %s) +// APCS-GNU: %[[a:.*]] = alloca { [1 x i32] } +// APCS-GNU: %[[gep:.*]] = getelementptr { [1 x i32] }* %[[a]], i32 0, i32 0 +// APCS-GNU: load [1 x i32]* %[[gep]] +// AAPCS: @g34(%struct.s34* %s) +// AAPCS: %[[a:.*]] = alloca { [1 x i32] } +// AAPCS: %[[gep:.*]] = getelementptr { [1 x i32] }* %[[a]], i32 0, i32 0 +// AAPCS: load [1 x i32]* %[[gep]] -- 2.7.4