[llvm] [InstCombine] fold `sub(zext(ptrtoint), zext(ptrtoint))` (PR #115369)

[Nikita Popov via llvm-commits]

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@@ -270,6 +270,36 @@ define i64 @test25(ptr %P, i64 %A){
   ret i64 %G
 }
 
+define i64 @zext_ptrtoint_sub_ptrtoint(ptr %p, i32 %offset) {
+; CHECK-LABEL: @zext_ptrtoint_sub_ptrtoint(
+; CHECK-NEXT:  %1 = sext i32 %offset to i64
+; CHECK-NEXT:  %A = getelementptr bfloat, ptr @Arr, i64 %1
+; CHECK-NEXT:  %2 = ptrtoint ptr %A to i64
+; CHECK-NEXT:  %C = and i64 %2, 4294967294
+; CHECK-NEXT:  %D = sub i64 %C, ptrtoint (ptr @Arr to i64)
+; CHECK-NEXT:  ret i64 %D
+  %A = getelementptr bfloat, ptr @Arr, i32 %offset
+  %B = ptrtoint ptr %A to i32
+  %C = zext i32 %B to i64
+  %D = sub i64 %C, ptrtoint (ptr @Arr to i64)
+  ret i64 %D
+}
+
+define i64 @ptrtoint_sub_zext_ptrtoint(ptr %p, i32 %offset) {
+; CHECK-LABEL: @ptrtoint_sub_zext_ptrtoint(
+; CHECK-NEXT:  %1 = sext i32 %offset to i64
+; CHECK-NEXT:  %A = getelementptr bfloat, ptr @Arr, i64 %1
+; CHECK-NEXT:  %2 = ptrtoint ptr %A to i64
+; CHECK-NEXT:  %C = and i64 %2, 4294967294
+; CHECK-NEXT:  %D = sub i64 ptrtoint (ptr @Arr to i64), %C
+; CHECK-NEXT:  ret i64 %D
+  %A = getelementptr bfloat, ptr @Arr, i32 %offset
+  %B = ptrtoint ptr %A to i32
+  %C = zext i32 %B to i64
+  %D = sub i64 ptrtoint (ptr @Arr to i64), %C
+  ret i64 %D
+}
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nikic wrote:

Are these also supposed to be negative tests for wrong bw?

https://github.com/llvm/llvm-project/pull/115369