diff options
| author | Michael Berg <michael_c_berg@apple.com> | 2018-06-05 18:49:47 +0000 |
|---|---|---|
| committer | Michael Berg <michael_c_berg@apple.com> | 2018-06-05 18:49:47 +0000 |
| commit | 96925fe0df7a628839eabb5886a0e59910713ab6 (patch) | |
| tree | 400aafdcd23c4192db8cca373fe9e5189186b1e2 | |
| parent | b89704fa6f6fc80c58bdacdadeb6d0dd4fa6e5d9 (diff) | |
| download | bcm5719-llvm-96925fe0df7a628839eabb5886a0e59910713ab6.tar.gz bcm5719-llvm-96925fe0df7a628839eabb5886a0e59910713ab6.zip | |
guard fneg with fmf sub flags
Summary: This change uses fmf subflags to guard optimizations as well as unsafe. These changes originated from D46483.
Reviewers: spatel, hfinkel
Reviewed By: spatel
Subscribers: nemanjai
Differential Revision: https://reviews.llvm.org/D47389
llvm-svn: 334037
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 6 | ||||
| -rw-r--r-- | llvm/test/CodeGen/PowerPC/fmf-propagation.ll | 15 |
2 files changed, 9 insertions, 12 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index 9dac51f33cd..bdecb8b37c4 100644 --- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -4049,10 +4049,10 @@ SDValue SelectionDAG::getNode(unsigned Opcode, const SDLoc &DL, EVT VT, break; case ISD::FNEG: // -(X-Y) -> (Y-X) is unsafe because when X==Y, -0.0 != +0.0 - if (getTarget().Options.UnsafeFPMath && OpOpcode == ISD::FSUB) - // FIXME: FNEG has no fast-math-flags to propagate; use the FSUB's flags? + if ((getTarget().Options.UnsafeFPMath || Flags.hasNoSignedZeros()) && + OpOpcode == ISD::FSUB) return getNode(ISD::FSUB, DL, VT, Operand.getOperand(1), - Operand.getOperand(0), Operand.getNode()->getFlags()); + Operand.getOperand(0), Flags); if (OpOpcode == ISD::FNEG) // --X -> X return Operand.getOperand(0); break; diff --git a/llvm/test/CodeGen/PowerPC/fmf-propagation.ll b/llvm/test/CodeGen/PowerPC/fmf-propagation.ll index 3a9c844c238..4c87c3dfbbd 100644 --- a/llvm/test/CodeGen/PowerPC/fmf-propagation.ll +++ b/llvm/test/CodeGen/PowerPC/fmf-propagation.ll @@ -460,28 +460,25 @@ define double @log2_approx(double %x) nounwind { ; -(X - Y) --> (Y - X) ; FMFDEBUG-LABEL: Optimized lowered selection DAG: %bb.0 'fneg_fsub_nozeros_1:' -; FMFDEBUG: fsub {{t[0-9]+}}, {{t[0-9]+}} +; FMFDEBUG: fsub nsz {{t[0-9]+}}, {{t[0-9]+}} ; FMFDEBUG: Type-legalized selection DAG: %bb.0 'fneg_fsub_nozeros_1:' ; GLOBALDEBUG-LABEL: Optimized lowered selection DAG: %bb.0 'fneg_fsub_nozeros_1:' -; GLOBALDEBUG: fsub {{t[0-9]+}}, {{t[0-9]+}} +; GLOBALDEBUG: fsub nsz {{t[0-9]+}}, {{t[0-9]+}} ; GLOBALDEBUG: Type-legalized selection DAG: %bb.0 'fneg_fsub_nozeros_1:' define float @fneg_fsub_nozeros_1(float %x, float %y, float %z) { ; FMF-LABEL: fneg_fsub_nozeros_1: ; FMF: # %bb.0: -; FMF-NEXT: xssubsp 0, 1, 2 -; FMF-NEXT: xxlxor 13, 13, 13 -; FMF-NEXT: xssubsp 1, 13, 0 +; FMF-NEXT: xssubsp 1, 2, 1 ; FMF-NEXT: blr ; ; GLOBAL-LABEL: fneg_fsub_nozeros_1: ; GLOBAL: # %bb.0: -; GLOBAL-NEXT: xssubsp 0, 1, 2 -; GLOBAL-NEXT: xxlxor 13, 13, 13 -; GLOBAL-NEXT: xssubsp 1, 13, 0 +; GLOBAL-NEXT: xssubsp 1, 2, 1 ; GLOBAL-NEXT: blr %neg = fsub float %x, %y - %add = fsub float 0.0, %neg + %add = fsub nsz float 0.0, %neg ret float %add } + |
