[PATCH] D68328: Fix occurrences that size and range of pointers are assumed to be the same.

Wed Oct 2 06:49:49 PDT 2019

Joe marked an inline comment as done.
Joe added inline comments.

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Comment at: llvm/test/Transforms/InstCombine/icmp-custom-dl.ll:11
 ; CHECK-NEXT:    [[GEP1:%.*]] = getelementptr inbounds i8, i8* [[FOO:%.*]], i32 8
-; CHECK-NEXT:    [[TMP1:%.*]] = ptrtoint i8* [[GEP1]] to i32
-; CHECK-NEXT:    [[USE:%.*]] = zext i32 [[TMP1]] to i64
+; CHECK-NEXT:    [[TMP1:%.*]] = ptrtoint i8* [[GEP1]] to i40
+; CHECK-NEXT:    [[USE:%.*]] = zext i40 [[TMP1]] to i64
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delena wrote:
> This change does not work for us. 
> Doing this change we added a way to specify type for "ptrtoint" transformation and for size of GEP index. If you do not specify the index type, this change should be NFC. What exactly does not work for you?
I don't believe that size of GEP index and type for "ptrtoint" transformation are the same thing. At least, that's how I interpreted langref: // 'The ‘ptrtoint’ instruction converts value to integer type ty2 by interpreting the pointer value as an integer'//. 

InstCombine was transforming 'ptrtoint i8* to i64' to 'ptrtoint i8* to i32', followed by a zext. Here, where the pointer size is 40 bits, that would mean 8 bits have been chopped off.

If you do not specify the index type, this change is NFC because index size defaults to pointer size.

Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D68328/new/

https://reviews.llvm.org/D68328