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9d9e29b4a8
inbounds GEPs. This isn't really necessary for simplifying pointer differences, but I'm planning to re-use the same code to simplify pointer comparisons where it is necessary. Since real code almost exclusively uses inbounds GEPs, it doesn't seem worth it to support the extra complexity of turning it on and off. If anyone would like that back, feel free to shout. Note that instcombine will still catch any of these patterns. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153418 91177308-0d34-0410-b5e6-96231b3b80d8
49 lines
1.6 KiB
LLVM
49 lines
1.6 KiB
LLVM
; RUN: opt < %s -instsimplify -S | FileCheck %s
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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"
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target triple = "x86_64-unknown-linux-gnu"
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define i64 @ptrdiff1(i8* %ptr) {
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; CHECK: @ptrdiff1
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; CHECK-NEXT: ret i64 42
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%first = getelementptr inbounds i8* %ptr, i32 0
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%last = getelementptr inbounds i8* %ptr, i32 42
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%first.int = ptrtoint i8* %first to i64
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%last.int = ptrtoint i8* %last to i64
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%diff = sub i64 %last.int, %first.int
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ret i64 %diff
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}
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define i64 @ptrdiff2(i8* %ptr) {
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; CHECK: @ptrdiff2
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; CHECK-NEXT: ret i64 42
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%first1 = getelementptr inbounds i8* %ptr, i32 0
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%first2 = getelementptr inbounds i8* %first1, i32 1
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%first3 = getelementptr inbounds i8* %first2, i32 2
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%first4 = getelementptr inbounds i8* %first3, i32 4
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%last1 = getelementptr inbounds i8* %first2, i32 48
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%last2 = getelementptr inbounds i8* %last1, i32 8
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%last3 = getelementptr inbounds i8* %last2, i32 -4
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%last4 = getelementptr inbounds i8* %last3, i32 -4
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%first.int = ptrtoint i8* %first4 to i64
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%last.int = ptrtoint i8* %last4 to i64
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%diff = sub i64 %last.int, %first.int
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ret i64 %diff
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}
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define i64 @ptrdiff3(i8* %ptr) {
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; Don't bother with non-inbounds GEPs.
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; CHECK: @ptrdiff3
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; CHECK: getelementptr
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; CHECK: sub
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; CHECK: ret
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%first = getelementptr i8* %ptr, i32 0
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%last = getelementptr i8* %ptr, i32 42
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%first.int = ptrtoint i8* %first to i64
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%last.int = ptrtoint i8* %last to i64
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%diff = sub i64 %last.int, %first.int
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ret i64 %diff
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}
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