[LoopUnroll] Use undef for phis with no value live
We would create a phi node with a zero initialized operand instead of
undef in the case where no value was originally available. This was
problematic for x86_mmx which has no null value.
llvm-svn: 241143
diff --git a/llvm/test/Transforms/LoopUnroll/X86/mmx.ll b/llvm/test/Transforms/LoopUnroll/X86/mmx.ll
new file mode 100644
index 0000000..2c4aa08
--- /dev/null
+++ b/llvm/test/Transforms/LoopUnroll/X86/mmx.ll
@@ -0,0 +1,24 @@
+; RUN: opt < %s -S -loop-unroll | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define x86_mmx @f() #0 {
+entry:
+ br label %for.body
+
+for.body: ; preds = %for.body, %entry
+ %phi = phi i32 [ 1, %entry ], [ %add, %for.body ]
+ %add = add i32 %phi, 1
+ %cmp = icmp eq i32 %phi, 0
+ br i1 %cmp, label %exit, label %for.body
+
+exit: ; preds = %for.body
+ %ret = phi x86_mmx [ undef, %for.body ]
+ ; CHECK: %[[ret_unr:.*]] = phi x86_mmx [ undef,
+ ; CHECK: %[[ret_ph:.*]] = phi x86_mmx [ undef,
+ ; CHECK: %[[ret:.*]] = phi x86_mmx [ %[[ret_unr]], {{.*}} ], [ %[[ret_ph]]
+ ; CHECK: ret x86_mmx %[[ret]]
+ ret x86_mmx %ret
+}
+
+attributes #0 = { "target-cpu"="x86-64" }