Optimize conditional branch on i1 phis with non-constant inputs.

This turns:

eq:
        %3 = icmp eq i32 %1, %2
        br label %join

ne:
        %4 = icmp ne i32 %1, %2
        br label %join

join:
        %5 = phi i1 [%3, %eq], [%4, %ne]
        br i1 %5, label %yes, label %no

=>

eq:
        %3 = icmp eq i32 %1, %2
        br i1 %3, label %yes, label %no

ne:
        %4 = icmp ne i32 %1, %2
        br i1 %4, label %yes, label %no


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69102 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 26 insertions, 0 deletions

diff --git a/test/Transforms/CondProp/phisimplify3.ll b/test/Transforms/CondProp/phisimplify3.ll
new file mode 100644
index 0000000..1678597
--- /dev/null
+++ b/test/Transforms/CondProp/phisimplify3.ll
@@ -0,0 +1,26 @@
+; RUN: llvm-as < %s | opt -condprop | llvm-dis | not grep phi
+
+define i32 @foo(i1, i32, i32) {
+prologue:
+	br i1 %0, label %eq, label %ne
+
+eq:		; preds = %prologue
+	store i32 0, i32* inttoptr (i32 10000 to i32*)
+	%3 = icmp eq i32 %1, %2		; <i1> [#uses=1]
+	br label %join
+
+ne:		; preds = %prologue
+	%4 = icmp ne i32 %1, %2		; <i1> [#uses=1]
+	br label %join
+
+join:		; preds = %ne, %eq
+	%5 = phi i1 [ %3, %eq ], [ %4, %ne ]		; <i1> [#uses=1]
+	br i1 %5, label %yes, label %no
+
+yes:		; preds = %join
+	store i32 0, i32* inttoptr (i32 20000 to i32*)
+	ret i32 5
+
+no:		; preds = %join
+	ret i32 20
+}