[llvm] [clang-tools-extra] [compiler-rt] [clang] [InferAddressSpaces] Fix constant replace to avoid modifying other functions (PR #70611)

[Matt Arsenault via cfe-commits]

================
@@ -0,0 +1,32 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 3
+; RUN: opt -assume-default-is-flat-addrspace -S -passes=infer-address-spaces < %s 2>&1 | FileCheck %s
+
+ at g = addrspace(1) global i32 0, align 4
+
+define ptr @f2() {
+; CHECK-LABEL: define ptr @f2() {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[X2:%.*]] = addrspacecast ptr addrspace(1) @g to ptr
+; CHECK-NEXT:    ret ptr [[X2]]
+;
+entry:
+  %x1 = addrspacecast ptr addrspacecast (ptr addrspace(1) @g to ptr) to ptr addrspace(1)
+  %x2 = addrspacecast ptr addrspace(1) %x1 to ptr
+  ret ptr %x2
+}
+
+define ptr @f3() #0 {
----------------
arsenm wrote:

Should add a comment explaining why f3 is here. Maybe also rename it to something descriptive 

https://github.com/llvm/llvm-project/pull/70611