From 4c5e8ccf748ec104bc5ff90b131306674f3cfecd Mon Sep 17 00:00:00 2001 From: Chandler Carruth Date: Wed, 10 Aug 2016 07:32:47 +0000 Subject: [x86] Fix a really nasty bug introduced in r276417 where alignment constraints were added to _mm256_broadcast_{pd,ps} intel intrinsics. The spec for these intrinics is ... pretty much silent on alignment. This is especially frustrating considering the amount of discussion of alignment in the load and store instrinsics. So I was forced to rely on the specification for the VBROADCASTF128 instruction. That instruction's spec is *also* completely silent on alignment. Fortunately, when it comes to the instruction's spec, silence is enough. There is no #GP fault option for an underaligned address so this instruction, and by inference the intrinsic, can read any alignment. As it happens, the old code worked exactly this way and in fact we have plenty of code that hands pointers with less than 16-byte alignment to these intrinsics. This code broke pretty spectacularly with this commit. Fortunately, the fix is super simple! Change a 16 to a 1, and ta da! Anyways, a lot of debugging for a really boring fix. =] llvm-svn: 278202 --- clang/lib/CodeGen/CGBuiltin.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'clang/lib/CodeGen/CGBuiltin.cpp') diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp index 5f47cb4e3d7..87a825d46ad 100644 --- a/clang/lib/CodeGen/CGBuiltin.cpp +++ b/clang/lib/CodeGen/CGBuiltin.cpp @@ -7020,7 +7020,7 @@ Value *CodeGenFunction::EmitX86BuiltinExpr(unsigned BuiltinID, case X86::BI__builtin_ia32_vbroadcastf128_pd256: case X86::BI__builtin_ia32_vbroadcastf128_ps256: { llvm::Type *DstTy = ConvertType(E->getType()); - return EmitX86SubVectorBroadcast(*this, Ops, DstTy, 128, 16); + return EmitX86SubVectorBroadcast(*this, Ops, DstTy, 128, 1); } case X86::BI__builtin_ia32_storehps: -- cgit v1.2.3