Resubmit "[CorrelatedValuePropagation] Fix prof branch_weights metadata handling for SwitchInst"

This reverts commit 5b32f60ec31ce136edac6f693538aeb6039f4ad0.
The fix is in commit 4f9e68148bd0dada2d6997625432385918ac2e2c.

This patch fixes the CorrelatedValuePropagation pass to keep
prof branch_weights metadata of SwitchInst consistent.
It makes use of SwitchInstProfUpdateWrapper.
New tests are added.

Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D62126

llvm-svn: 362583

1 files changed, 119 insertions, 0 deletions

diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/profmd.ll b/llvm/test/Transforms/CorrelatedValuePropagation/profmd.ll
new file mode 100644
index 00000000000..493b4c2273e
--- /dev/null
+++ b/llvm/test/Transforms/CorrelatedValuePropagation/profmd.ll
@@ -0,0 +1,119 @@
+; RUN: opt < %s -correlated-propagation -S | FileCheck %s
+
+; Removed several cases from switch.
+define i32 @switch1(i32 %s) {
+; CHECK-LABEL: @switch1(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[S:%.*]], 0
+; CHECK-NEXT:    br i1 [[CMP]], label [[NEGATIVE:%.*]], label [[OUT:%.*]]
+;
+entry:
+  %cmp = icmp slt i32 %s, 0
+  br i1 %cmp, label %negative, label %out
+
+negative:
+; CHECK:       negative:
+; CHECK-NEXT:    switch i32 [[S]], label [[OUT]] [
+; CHECK-NEXT:    i32 -2, label [[NEXT:%.*]]
+; CHECK-NEXT:    i32 -1, label [[NEXT]]
+  switch i32 %s, label %out [
+  i32 0, label %out
+  i32 1, label %out
+  i32 -1, label %next
+  i32 -2, label %next
+  i32 2, label %out
+  i32 3, label %out
+; CHECK-NEXT: !prof ![[MD0:[0-9]+]]
+  ], !prof !{!"branch_weights", i32 99, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6}
+
+out:
+  %p = phi i32 [ 1, %entry ], [ -1, %negative ], [ -1, %negative ], [ -1, %negative ], [ -1, %negative ], [ -1, %negative ]
+  ret i32 %p
+
+next:
+  %q = phi i32 [ 0, %negative ], [ 0, %negative ]
+  ret i32 %q
+}
+
+; Removed all cases from switch.
+define i32 @switch2(i32 %s) {
+; CHECK-LABEL: @switch2(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[S:%.*]], 0
+; CHECK-NEXT:    br i1 [[CMP]], label [[POSITIVE:%.*]], label [[OUT:%.*]]
+;
+entry:
+  %cmp = icmp sgt i32 %s, 0
+  br i1 %cmp, label %positive, label %out
+
+positive:
+  switch i32 %s, label %out [
+  i32 0, label %out
+  i32 -1, label %next
+  i32 -2, label %next
+  ], !prof !{!"branch_weights", i32 99, i32 1, i32 2, i32 3}
+
+out:
+  %p = phi i32 [ -1, %entry ], [ 1, %positive ], [ 1, %positive ]
+  ret i32 %p
+
+next:
+  %q = phi i32 [ 0, %positive ], [ 0, %positive ]
+  ret i32 %q
+}
+
+; Change switch into conditional branch.
+define i32 @switch3(i32 %s) {
+; CHECK-LABEL: @switch3(
+;
+entry:
+  %cmp = icmp sgt i32 %s, 0
+  br i1 %cmp, label %positive, label %out
+
+positive:
+; CHECK:      positive:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 %s, 1
+; CHECK-NEXT:    br i1 [[CMP]], label [[NEXT:%.*]], label [[OUT:%.*]], !prof ![[MD1:[0-9]+]]
+  switch i32 %s, label %out [
+  i32 1, label %next
+  i32 -1, label %next
+  i32 -2, label %next
+  ], !prof !{!"branch_weights", i32 99, i32 1, i32 2, i32 3}
+
+out:
+  %p = phi i32 [ -1, %entry ], [ 1, %positive ]
+  ret i32 %p
+
+next:
+  %q = phi i32 [ 0, %positive ], [ 0, %positive ], [ 0, %positive ]
+  ret i32 %q
+}
+
+; Removed all cases from switch.
+define i32 @switch4(i32 %s) {
+; CHECK-LABEL: @switch4(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[S:%.*]], 0
+; CHECK-NEXT:    br i1 [[CMP]], label [[NEGATIVE:%.*]], label [[OUT:%.*]]
+;
+entry:
+  %cmp = icmp slt i32 %s, 0
+  br i1 %cmp, label %negative, label %out
+
+negative:
+; CHECK:       negative:
+; CHECK-NEXT:    br label %out
+  switch i32 %s, label %out [
+  i32 0, label %out
+  i32 1, label %out
+  i32 2, label %out
+  i32 3, label %out
+  ], !prof !{!"branch_weights", i32 99, i32 1, i32 2, i32 3, i32 4}
+
+out:
+  %p = phi i32 [ 1, %entry ], [ -1, %negative ], [ -1, %negative ], [ -1, %negative ], [ -1, %negative ], [ -1, %negative ]
+  ret i32 %p
+}
+
+; CHECK: ![[MD0]] = !{!"branch_weights", i32 99, i32 4, i32 3}
+; CHECK: ![[MD1]] = !{!"branch_weights", i32 1, i32 99}