commit 363e4b90c0a8dfca87ac847001158c743491c06f
author Owen Anderson <resistor@mac.com> Wed May 02 21:32:35 2012 +0000
committer Owen Anderson <resistor@mac.com> Wed May 02 21:32:35 2012 +0000
tree 298a6f6456c4bede793a06dbc89bd21188b08005
parent 4599613dec76683aa1630a4a02082e0dc8ec2706

Teach DAG combine that multiplication by 1.0 can always be constant folded.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156023 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/SelectionDAG/DAGCombiner.cpp

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index e72c8d5..b8f08bf 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -5715,6 +5715,9 @@
   if (DAG.getTarget().Options.UnsafeFPMath &&
       ISD::isBuildVectorAllZeros(N1.getNode()))
     return N1;
+  // fold (fmul A, 1.0) -> A
+  if (N1CFP && N1CFP->isExactlyValue(1.0))
+    return N0;
   // fold (fmul X, 2.0) -> (fadd X, X)
   if (N1CFP && N1CFP->isExactlyValue(+2.0))
     return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0, N0);