Fix 9216 - Endless loop in InstCombine pass.

The pattern "A&(A^B) -> A & ~B" recreated itself because ~B is
actually a xor -1.

llvm-svn: 125557

1 files changed, 19 insertions, 0 deletions

diff --git a/llvm/test/Transforms/InstCombine/2011-02-14-InfLoop.ll b/llvm/test/Transforms/InstCombine/2011-02-14-InfLoop.ll
new file mode 100644
index 00000000000..6d8a7ddbe46
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/2011-02-14-InfLoop.ll
@@ -0,0 +1,19 @@
+; This testcase causes an infinite loop in the instruction combiner,
+; because it changes a pattern and the original pattern is almost
+; identical to the newly-generated pattern.
+; RUN: opt < %s -instcombine -disable-output
+
+;PR PR9216
+
+target triple = "x86_64-unknown-linux-gnu"
+
+define <4 x float> @m_387(i8* noalias nocapture %A, i8* nocapture %B, <4 x i1> %C) nounwind {
+entry:
+  %movcsext20 = sext <4 x i1> %C to <4 x i32>
+  %tmp2389 = xor <4 x i32> %movcsext20, <i32 -1, i32 -1, i32 -1, i32 -1>
+  %movcand25 = and <4 x i32> %tmp2389, <i32 undef, i32 undef, i32 undef, i32 -1>
+  %movcor26 = or <4 x i32> %movcand25, zeroinitializer
+  %L2 = bitcast <4 x i32> %movcor26 to <4 x float>
+  %L3 = shufflevector <4 x float> zeroinitializer, <4 x float> %L2, <4 x i32> <i32 0, i32 1, i32 2, i32 7>
+  ret <4 x float> %L3
+}