a005c1ac4f
Patch D56593 by @courbet results in calls to `bcmp()` in some cases, should the target support the it. Unless `TTI::MemCmpExpansionOptions()` is overridden by the target. In a proprietary benchmark we see a performance drop of about 12% on PNG compression before this patch, though it passes all tests. This patch mirrors X86 for AArch64 and initializes `TTI::MemCmpExpansionOptions()` to then expand calls to `bcmp()` when appropriate. No tuning of the parameters was performed, but, at this point, it's enough to recover the performance drop above. This problem also exists on ARM. Once a consensus is reached for AArch64, we can work to fix ARM as well. Authors: - Evandro Menezes (@evandro) <e.menezes@samsung.com> - Brian Rzycki (@brzycki) <b.rzycki@samsung.com> Differential revision: https://reviews.llvm.org/D64805 llvm-svn: 367898
45 lines
1.1 KiB
LLVM
45 lines
1.1 KiB
LLVM
; RUN: llc -O2 < %s -mtriple=aarch64-linux-gnu | FileCheck %s --check-prefixes=CHECK,CHECKN
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; RUN: llc -O2 < %s -mtriple=aarch64-linux-gnu -mattr=strict-align | FileCheck %s --check-prefixes=CHECK,CHECKS
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declare i32 @bcmp(i8*, i8*, i64) nounwind readonly
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declare i32 @memcmp(i8*, i8*, i64) nounwind readonly
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define i1 @bcmp_b2(i8* %s1, i8* %s2) {
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entry:
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%bcmp = call i32 @bcmp(i8* %s1, i8* %s2, i64 15)
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%ret = icmp eq i32 %bcmp, 0
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ret i1 %ret
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; CHECK-LABEL: bcmp_b2:
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; CHECK-NOT: bl bcmp
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; CHECKN: ldr x
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; CHECKN-NEXT: ldr x
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; CHECKN-NEXT: ldur x
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; CHECKN-NEXT: ldur x
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; CHECKS: ldr x
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; CHECKS-NEXT: ldr x
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; CHECKS-NEXT: ldr w
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; CHECKS-NEXT: ldr w
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; CHECKS-NEXT: ldrh w
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; CHECKS-NEXT: ldrh w
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; CHECKS-NEXT: ldrb w
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; CHECKS-NEXT: ldrb w
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}
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define i1 @bcmp_bs(i8* %s1, i8* %s2) optsize {
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entry:
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%memcmp = call i32 @memcmp(i8* %s1, i8* %s2, i64 31)
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%ret = icmp eq i32 %memcmp, 0
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ret i1 %ret
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; CHECK-LABEL: bcmp_bs:
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; CHECKN-NOT: bl memcmp
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; CHECKN: ldp x
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; CHECKN-NEXT: ldp x
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; CHECKN-NEXT: ldr x
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; CHECKN-NEXT: ldr x
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; CHECKN-NEXT: ldur x
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; CHECKN-NEXT: ldur x
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; CHECKS: bl memcmp
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}
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