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      1 ; RUN: opt < %s -instsimplify -S | FileCheck %s
      2 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
      3 target triple = "x86_64-unknown-linux-gnu"
      4 
      5 define i64 @ptrdiff1(i8* %ptr) {
      6 ; CHECK: @ptrdiff1
      7 ; CHECK-NEXT: ret i64 42
      8 
      9   %first = getelementptr inbounds i8* %ptr, i32 0
     10   %last = getelementptr inbounds i8* %ptr, i32 42
     11   %first.int = ptrtoint i8* %first to i64
     12   %last.int = ptrtoint i8* %last to i64
     13   %diff = sub i64 %last.int, %first.int
     14   ret i64 %diff
     15 }
     16 
     17 define i64 @ptrdiff2(i8* %ptr) {
     18 ; CHECK: @ptrdiff2
     19 ; CHECK-NEXT: ret i64 42
     20 
     21   %first1 = getelementptr inbounds i8* %ptr, i32 0
     22   %first2 = getelementptr inbounds i8* %first1, i32 1
     23   %first3 = getelementptr inbounds i8* %first2, i32 2
     24   %first4 = getelementptr inbounds i8* %first3, i32 4
     25   %last1 = getelementptr inbounds i8* %first2, i32 48
     26   %last2 = getelementptr inbounds i8* %last1, i32 8
     27   %last3 = getelementptr inbounds i8* %last2, i32 -4
     28   %last4 = getelementptr inbounds i8* %last3, i32 -4
     29   %first.int = ptrtoint i8* %first4 to i64
     30   %last.int = ptrtoint i8* %last4 to i64
     31   %diff = sub i64 %last.int, %first.int
     32   ret i64 %diff
     33 }
     34 
     35 define i64 @ptrdiff3(i8* %ptr) {
     36 ; Don't bother with non-inbounds GEPs.
     37 ; CHECK: @ptrdiff3
     38 ; CHECK: getelementptr
     39 ; CHECK: sub
     40 ; CHECK: ret
     41 
     42   %first = getelementptr i8* %ptr, i32 0
     43   %last = getelementptr i8* %ptr, i32 42
     44   %first.int = ptrtoint i8* %first to i64
     45   %last.int = ptrtoint i8* %last to i64
     46   %diff = sub i64 %last.int, %first.int
     47   ret i64 %diff
     48 }
     49