diff --git a/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/lib/Transforms/InstCombine/InstCombineAddSub.cpp index c22249527b9..47223c3b358 100644 --- a/lib/Transforms/InstCombine/InstCombineAddSub.cpp +++ b/lib/Transforms/InstCombine/InstCombineAddSub.cpp @@ -354,6 +354,10 @@ Instruction *InstCombiner::visitFAdd(BinaryOperator &I) { if (Value *V = SimplifyFAddInst(LHS, RHS, I.getFastMathFlags(), TD)) return ReplaceInstUsesWith(I, V); + if (isa(RHS) && isa(LHS)) + if (Instruction *NV = FoldOpIntoPhi(I)) + return NV; + // -A + B --> B - A // -A + -B --> -(A + B) if (Value *LHSV = dyn_castFNegVal(LHS)) diff --git a/test/Transforms/InstCombine/fold-phi.ll b/test/Transforms/InstCombine/fold-phi.ll new file mode 100644 index 00000000000..bd01d58aa58 --- /dev/null +++ b/test/Transforms/InstCombine/fold-phi.ll @@ -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 +}