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35f00e690f
Hacker's Delight 10-17: when C is constant, the result of X % C == 0 can be computed more cheaply without actually calculating the remainder. The motivation is discussed here: https://bugs.llvm.org/show_bug.cgi?id=35479. Patch by: hermord (Dmytro Shynkevych)! For https://reviews.llvm.org/D50222 llvm-svn: 341047
42 lines
1.3 KiB
LLVM
42 lines
1.3 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
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; RUN: llc -mtriple=aarch64-unknown-linux-gnu < %s | FileCheck %s
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; On AArch64, division in expensive. BuildRemEqFold should therefore run even
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; when optimizing for size. Only optimizing for minimum size retains a plain div.
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define i32 @test_minsize(i32 %X) optsize minsize nounwind readnone {
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; CHECK-LABEL: test_minsize:
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; CHECK: // %bb.0:
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; CHECK-NEXT: mov w8, #5
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; CHECK-NEXT: udiv w8, w0, w8
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; CHECK-NEXT: add w8, w8, w8, lsl #2
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; CHECK-NEXT: mov w9, #-10
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; CHECK-NEXT: cmp w0, w8
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; CHECK-NEXT: mov w8, #42
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; CHECK-NEXT: csel w0, w8, w9, eq
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; CHECK-NEXT: ret
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%rem = urem i32 %X, 5
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%cmp = icmp eq i32 %rem, 0
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%ret = select i1 %cmp, i32 42, i32 -10
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ret i32 %ret
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}
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define i32 @test_optsize(i32 %X) optsize nounwind readnone {
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; CHECK-LABEL: test_optsize:
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; CHECK: // %bb.0:
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; CHECK-NEXT: mov w8, #52429
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; CHECK-NEXT: movk w8, #52428, lsl #16
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; CHECK-NEXT: umull x8, w0, w8
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; CHECK-NEXT: lsr x8, x8, #34
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; CHECK-NEXT: add w8, w8, w8, lsl #2
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; CHECK-NEXT: mov w9, #-10
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; CHECK-NEXT: cmp w0, w8
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; CHECK-NEXT: mov w8, #42
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; CHECK-NEXT: csel w0, w8, w9, eq
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; CHECK-NEXT: ret
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%rem = urem i32 %X, 5
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%cmp = icmp eq i32 %rem, 0
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%ret = select i1 %cmp, i32 42, i32 -10
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ret i32 %ret
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}
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