From fa54acedd1fd1183143c0a7f4b77554fd8cdb1ec Mon Sep 17 00:00:00 2001 From: Sanjay Patel Date: Mon, 14 Dec 2015 21:59:03 +0000 Subject: add fast-math-flags to 'call' instructions (PR21290) This patch adds optional fast-math-flags (the same that apply to fmul/fadd/fsub/fdiv/frem/fcmp) to call instructions in IR. Follow-up patches would use these flags in LibCallSimplifier, add support to clang, and extend FMF to the DAG for calls. Motivating example: %y = fmul fast float %x, %x %z = tail call float @sqrtf(float %y) We'd like to be able to optimize sqrt(x*x) into fabs(x). We do this today using a function-wide attribute for unsafe-math, but we really want to trigger on the instructions themselves: %z = tail call fast float @sqrtf(float %y) because in an LTO build it's possible that calls with fast semantics have been inlined into a function with non-fast semantics. The code changes and tests are based on the recent commits that added "notail": http://reviews.llvm.org/rL252368 and added FMF to fcmp: http://reviews.llvm.org/rL241901 Differential Revision: http://reviews.llvm.org/D14707 llvm-svn: 255555 --- llvm/lib/Bitcode/Writer/BitcodeWriter.cpp | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'llvm/lib/Bitcode/Writer') diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp index dd4a16d985f..e34ce5ac430 100644 --- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp +++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp @@ -2153,11 +2153,17 @@ static void WriteInstruction(const Instruction &I, unsigned InstID, Code = bitc::FUNC_CODE_INST_CALL; Vals.push_back(VE.getAttributeID(CI.getAttributes())); + + unsigned Flags = GetOptimizationFlags(&I); Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV | unsigned(CI.isTailCall()) << bitc::CALL_TAIL | unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL | 1 << bitc::CALL_EXPLICIT_TYPE | - unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL); + unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL | + unsigned(Flags != 0) << bitc::CALL_FMF); + if (Flags != 0) + Vals.push_back(Flags); + Vals.push_back(VE.getTypeID(FTy)); PushValueAndType(CI.getCalledValue(), InstID, Vals, VE); // Callee -- cgit v1.2.3