From 07acee7a09c4895904f827bf56cf15f6bf8ef9f6 Mon Sep 17 00:00:00 2001
From: Michael Ilseman <milseman@apple.com>
Date: Fri, 14 Dec 2012 22:08:26 +0000
Subject: [PATCH] Add back FoldOpIntoPhi optimizations with fix. Included test
cases to help catch these errors and to test the presence of the optimization
itself
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170248 91177308-0d34-0410-b5e6-96231b3b80d8
---
.../InstCombine/InstCombineAddSub.cpp | 4 ++
test/Transforms/InstCombine/fold-phi.ll | 39 +++++++++++++++++++
2 files changed, 43 insertions(+)
create mode 100644 test/Transforms/InstCombine/fold-phi.ll
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<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))
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
+}