[SimplifyCFG] Revise common code sinking

- Fix the case where more than 1 common instructions derived from the same
  operand cannot be sunk. When a pair of value has more than 1 derived values
  in both branches, only 1 derived value could be sunk.
- Replace BB1 -> (BB2, PN) map with joint value map, i.e.
  map of (BB1, BB2) -> PN, which is more accurate to track common ops.

llvm-svn: 224757

1 files changed, 32 insertions, 2 deletions

diff --git a/llvm/test/Transforms/SimplifyCFG/sink-common-code.ll b/llvm/test/Transforms/SimplifyCFG/sink-common-code.ll
index 28d72793828..cdb6ed29d85 100644
--- a/llvm/test/Transforms/SimplifyCFG/sink-common-code.ll
+++ b/llvm/test/Transforms/SimplifyCFG/sink-common-code.ll
@@ -4,7 +4,7 @@ define zeroext i1 @test1(i1 zeroext %flag, i32 %blksA, i32 %blksB, i32 %nblks) {
 entry:
   br i1 %flag, label %if.then, label %if.else
 
-; CHECK: test1
+; CHECK-LABEL: test1
 ; CHECK: add
 ; CHECK: select
 ; CHECK: icmp
@@ -30,7 +30,7 @@ define zeroext i1 @test2(i1 zeroext %flag, i32 %blksA, i32 %blksB, i32 %nblks) {
 entry:
   br i1 %flag, label %if.then, label %if.else
 
-; CHECK: test2
+; CHECK-LABEL: test2
 ; CHECK: add
 ; CHECK: select
 ; CHECK: icmp
@@ -51,3 +51,33 @@ if.end:
   %tobool4 = icmp ne i8 %obeys.0, 0
   ret i1 %tobool4
 }
+
+declare i32 @foo(i32, i32) nounwind readnone
+
+define i32 @test3(i1 zeroext %flag, i32 %x, i32 %y) {
+entry:
+  br i1 %flag, label %if.then, label %if.else
+
+if.then:
+  %x0 = call i32 @foo(i32 %x, i32 0) nounwind readnone
+  %y0 = call i32 @foo(i32 %x, i32 1) nounwind readnone
+  br label %if.end
+
+if.else:
+  %x1 = call i32 @foo(i32 %y, i32 0) nounwind readnone
+  %y1 = call i32 @foo(i32 %y, i32 1) nounwind readnone
+  br label %if.end
+
+if.end:
+  %xx = phi i32 [ %x0, %if.then ], [ %x1, %if.else ]
+  %yy = phi i32 [ %y0, %if.then ], [ %y1, %if.else ]
+  %ret = add i32 %xx, %yy
+  ret i32 %ret
+}
+
+; CHECK-LABEL: test3
+; CHECK: select
+; CHECK: call
+; CHECK: call
+; CHECK: add
+; CHECK-NOT: br