Add back FoldOpIntoPhi optimizations with fix. Included test cases to help catch these errors and to test the presence of the optimization itself

llvm-svn: 170248

1 files changed, 39 insertions, 0 deletions

diff --git a/llvm/test/Transforms/InstCombine/fold-phi.ll b/llvm/test/Transforms/InstCombine/fold-phi.ll
new file mode 100644
index 00000000000..bd01d58aa58
--- /dev/null
+++ b/llvm/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
+}