Don't do the X * 0.0 -> 0.0 transformation in instcombine, because
instcombine doesn't know when it's safe. To partially compensate
for this, introduce new code to do this transformation in
dagcombine, which can use UnsafeFPMath.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72872 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 4c1710d..5d1b2a3 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -4019,6 +4019,9 @@
// fold (fmul A, 0) -> 0
if (UnsafeFPMath && N1CFP && N1CFP->getValueAPF().isZero())
return N1;
+ // fold (fmul A, 0) -> 0, vector edition.
+ if (UnsafeFPMath && ISD::isBuildVectorAllZeros(N1.getNode()))
+ return N1;
// fold (fmul X, 2.0) -> (fadd X, X)
if (N1CFP && N1CFP->isExactlyValue(+2.0))
return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0, N0);
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 2c645e4..c2c884e 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2807,16 +2807,19 @@
case ISD::ADDC:
case ISD::ADDE:
case ISD::SUB:
- case ISD::FADD:
- case ISD::FSUB:
- case ISD::FMUL:
- case ISD::FDIV:
- case ISD::FREM:
case ISD::UDIV:
case ISD::SDIV:
case ISD::UREM:
case ISD::SREM:
return N2; // fold op(arg1, undef) -> undef
+ case ISD::FADD:
+ case ISD::FSUB:
+ case ISD::FMUL:
+ case ISD::FDIV:
+ case ISD::FREM:
+ if (UnsafeFPMath)
+ return N2;
+ break;
case ISD::MUL:
case ISD::AND:
case ISD::SRL: