[llvm] [ValueTracking] Skip incoming values that are the same as the phi in `isGuaranteedNotToBeUndefOrPoison` (PR #130111)

[via llvm-commits]

================
@@ -0,0 +1,85 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -S -passes=instsimplify < %s | FileCheck %s
+
+; Test `%r` can be replaced by `%nonpoison`.
+
+define i32 @other_noundef() {
+; CHECK-LABEL: define i32 @other_noundef() {
+; CHECK-NEXT:  [[START:.*]]:
+; CHECK-NEXT:    br label %[[LOOP:.*]]
+; CHECK:       [[LOOP]]:
+; CHECK-NEXT:    [[NONPOISON:%.*]] = phi i32 [ 0, %[[START]] ], [ [[NONPOISON]], %[[BB0:.*]] ], [ 1, %[[BB1:.*]] ]
+; CHECK-NEXT:    [[I:%.*]] = call i32 @opaque()
+; CHECK-NEXT:    switch i32 [[I]], label %[[EXIT:.*]] [
+; CHECK-NEXT:      i32 0, label %[[BB0]]
+; CHECK-NEXT:      i32 1, label %[[BB1]]
+; CHECK-NEXT:    ]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    ret i32 [[NONPOISON]]
+; CHECK:       [[BB0]]:
+; CHECK-NEXT:    br label %[[LOOP]]
+; CHECK:       [[BB1]]:
+; CHECK-NEXT:    br label %[[LOOP]]
+;
+start:
+  br label %loop
+
+loop:
+  %nonpoison = phi i32 [ 0, %start ], [ %nonpoison, %bb0 ], [ 1, %bb1 ]
+  %i = call i32 @opaque()
+  switch i32 %i, label %exit [
+  i32 0, label %bb0
+  i32 1, label %bb1
+  ]
+
+exit:
+  %r = freeze i32 %nonpoison
+  ret i32 %r
+
+bb0:
+  br label %loop
+
+bb1:
+  br label %loop
+}
+
+define i32 @other_poison() {
+; CHECK-LABEL: define i32 @other_poison() {
+; CHECK-NEXT:  [[START:.*:]]
+; CHECK-NEXT:    br label %[[LOOP:.*]]
+; CHECK:       [[LOOP]]:
+; CHECK-NEXT:    [[I:%.*]] = call i32 @opaque()
+; CHECK-NEXT:    switch i32 [[I]], label %[[EXIT:.*]] [
+; CHECK-NEXT:      i32 0, label %[[BB0:.*]]
+; CHECK-NEXT:      i32 1, label %[[BB1:.*]]
+; CHECK-NEXT:    ]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    ret i32 0
+; CHECK:       [[BB0]]:
+; CHECK-NEXT:    br label %[[LOOP]]
+; CHECK:       [[BB1]]:
+; CHECK-NEXT:    br label %[[LOOP]]
+;
+start:
+  br label %loop
+
+loop:
+  %maypoison = phi i32 [ 0, %start ], [ %maypoison, %bb0 ], [ poison, %bb1 ]
----------------
DianQK wrote:

Yes, I noticed that when I rechecked the PR.

https://github.com/llvm/llvm-project/pull/130111