544a6aa267
And another step towards transforms not introducing inttoptr and/or ptrtoint casts that weren't there already. As we've been establishing (see D88788/D88789), if there is a int<->ptr cast, it basically must stay as-is, we can't do much with it. I've looked, and the most source of new such casts being introduces, as far as i can tell, is this transform, which, ironically, tries to reduce count of casts.. On vanilla llvm test-suite + RawSpeed, @ `-O3`, this results in -33.58% less `IntToPtr`s (19014 -> 12629) and +76.20% more `PtrToInt`s (18589 -> 32753), which is an increase of +20.69% in total. However just on RawSpeed, where i know there are basically none `IntToPtr` in the original source code, this results in -99.27% less `IntToPtr`s (2724 -> 20) and +82.92% more `PtrToInt`s (4513 -> 8255). which is again an increase of 14.34% in total. To me this does seem like the step in the right direction, we end up with strictly less `IntToPtr`, but strictly more `PtrToInt`, which seems like a reasonable trade-off. See https://reviews.llvm.org/D88860 / https://reviews.llvm.org/D88995 for some more discussion on the subject. (Eventually, `CastInst::isNoopCast()`/`CastInst::isEliminableCastPair` should be taught about this, yes) Reviewed By: nlopes, nikic Differential Revision: https://reviews.llvm.org/D88979
39 lines
1.2 KiB
LLVM
39 lines
1.2 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt < %s -instcombine -S | FileCheck %s
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target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-unknown-linux-gnu"
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; Function Attrs: readonly uwtable
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define i1 @dot_ref_s(i32** noalias nocapture readonly dereferenceable(8)) {
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; CHECK-LABEL: @dot_ref_s(
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; CHECK-NEXT: entry-block:
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; CHECK-NEXT: ret i1 false
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;
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entry-block:
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%loadedptr = load i32*, i32** %0, align 8, !nonnull !0
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%ptrtoint = ptrtoint i32* %loadedptr to i64
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%inttoptr = inttoptr i64 %ptrtoint to i32*
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%switchtmp = icmp eq i32* %inttoptr, null
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ret i1 %switchtmp
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}
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; Function Attrs: readonly uwtable
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define i64* @function(i64* noalias nocapture readonly dereferenceable(8)) {
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; CHECK-LABEL: @function(
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; CHECK-NEXT: entry-block:
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; CHECK-NEXT: [[LOADED:%.*]] = load i64, i64* [[TMP0:%.*]], align 8, [[RNG0:!range !.*]]
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; CHECK-NEXT: [[INTTOPTR:%.*]] = inttoptr i64 [[LOADED]] to i64*
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; CHECK-NEXT: ret i64* [[INTTOPTR]]
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;
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entry-block:
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%loaded = load i64, i64* %0, align 8, !range !1
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%inttoptr = inttoptr i64 %loaded to i64*
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ret i64* %inttoptr
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}
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!0 = !{}
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!1 = !{i64 1, i64 140737488355327}
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