[llvm-commits] [llvm] r170248 - in /llvm/trunk: lib/Transforms/InstCombine/InstCombineAddSub.cpp test/Transforms/InstCombine/fold-phi.ll

[Michael Ilseman]

Author: milseman
Date: Fri Dec 14 16:08:26 2012
New Revision: 170248

URL: http://llvm.org/viewvc/llvm-project?rev=170248&view=rev
Log:
Add back FoldOpIntoPhi optimizations with fix. Included test cases to help catch these errors and to test the presence of the optimization itself

Added:
    llvm/trunk/test/Transforms/InstCombine/fold-phi.ll
Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp?rev=170248&r1=170247&r2=170248&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp Fri Dec 14 16:08:26 2012
@@ -354,6 +354,10 @@
   if (Value *V = SimplifyFAddInst(LHS, RHS, I.getFastMathFlags(), TD))
     return ReplaceInstUsesWith(I, V);
 
+  if (isa<Constant>(RHS) && isa<PHINode>(LHS))
+    if (Instruction *NV = FoldOpIntoPhi(I))
+      return NV;
+
   // -A + B  -->  B - A
   // -A + -B  -->  -(A + B)
   if (Value *LHSV = dyn_castFNegVal(LHS))

Added: llvm/trunk/test/Transforms/InstCombine/fold-phi.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/fold-phi.ll?rev=170248&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/fold-phi.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/fold-phi.ll Fri Dec 14 16:08:26 2012
@@ -0,0 +1,39 @@
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+; CHECK: no_crash
+define float @no_crash(float %a) nounwind {
+entry:
+  br label %for.body
+
+for.body:
+  %sum.057 = phi float [ 0.000000e+00, %entry ], [ %add5, %bb0 ]
+  %add5 = fadd float %sum.057, %a    ; PR14592
+  br i1 undef, label %bb0, label %end
+
+bb0:
+  br label %for.body
+
+end:
+  ret float %add5
+}
+
+; CHECK: fold_phi
+define float @fold_phi(float %a) nounwind {
+entry:
+  br label %for.body
+
+for.body:
+; CHECK: phi float
+; CHECK-NEXT: br i1 undef
+  %sum.057 = phi float [ 0.000000e+00, %entry ], [ %add5, %bb0 ]
+  %add5 = fadd float %sum.057, 1.0 ;; Should be moved to the latch!
+  br i1 undef, label %bb0, label %end
+
+; CHECK: bb0:
+bb0:
+; CHECK: fadd float
+  br label %for.body
+
+end:
+  ret float %add5
+}