use getPredicateOnEdge to fold comparisons through PHI nodes,
which implements GCC PR18046. This also gets us 360 more
jump threads on 176.gcc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86953 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Transforms/JumpThreading/basic.ll b/test/Transforms/JumpThreading/basic.ll
index 03ce12e..07b3b0c 100644
--- a/test/Transforms/JumpThreading/basic.ll
+++ b/test/Transforms/JumpThreading/basic.ll
@@ -349,6 +349,38 @@
ret i32 4
}
+;; Correlated value through boolean expression. GCC PR18046.
+define void @test12(i32 %A) {
+; CHECK: @test12
+entry:
+ %cond = icmp eq i32 %A, 0
+ br i1 %cond, label %bb, label %bb1
+; Should branch to the return block instead of through BB1.
+; CHECK: entry:
+; CHECK-NEXT: %cond = icmp eq i32 %A, 0
+; CHECK-NEXT: br i1 %cond, label %bb1, label %return
+
+bb:
+ %B = call i32 @test10f2()
+ br label %bb1
+
+bb1:
+ %C = phi i32 [ %A, %entry ], [ %B, %bb ]
+ %cond4 = icmp eq i32 %C, 0
+ br i1 %cond4, label %bb2, label %return
+
+; CHECK: bb1:
+; CHECK-NEXT: %B = call i32 @test10f2()
+; CHECK-NEXT: %cond4 = icmp eq i32 %B, 0
+; CHECK-NEXT: br i1 %cond4, label %bb2, label %return
+
+bb2:
+ %D = call i32 @test10f2()
+ ret void
+
+return:
+ ret void
+}
;;; Duplicate condition to avoid xor of cond.