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https://github.com/c64scene-ar/llvm-6502.git
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8d7285d0e5
of a constant had a minor typo introduced when copying it from the book, which caused it to favor negative approximations over positive approximations in many cases. Positive approximations require fewer operations beyond the multiplication. In the case of division by 3, we still generate code that is a single instruction larger than GCC's code. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126097 91177308-0d34-0410-b5e6-96231b3b80d8
63 lines
1.5 KiB
LLVM
63 lines
1.5 KiB
LLVM
; RUN: llc < %s -mtriple=i686-pc-linux-gnu -asm-verbose=0 | FileCheck %s
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target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32"
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target triple = "i686-pc-linux-gnu"
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define zeroext i16 @test1(i16 zeroext %x) nounwind {
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entry:
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%div = udiv i16 %x, 33
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ret i16 %div
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; CHECK: test1:
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; CHECK: imull $63551, %eax, %eax
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; CHECK-NEXT: shrl $21, %eax
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; CHECK-NEXT: ret
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}
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define zeroext i16 @test2(i8 signext %x, i16 zeroext %c) nounwind readnone ssp noredzone {
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entry:
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%div = udiv i16 %c, 3
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ret i16 %div
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; CHECK: test2:
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; CHECK: imull $43691, %eax, %eax
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; CHECK-NEXT: shrl $17, %eax
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; CHECK-NEXT: ret
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}
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define zeroext i8 @test3(i8 zeroext %x, i8 zeroext %c) nounwind readnone ssp noredzone {
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entry:
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%div = udiv i8 %c, 3
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ret i8 %div
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; CHECK: test3:
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; CHECK: movzbl 8(%esp), %eax
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; CHECK-NEXT: imull $171, %eax, %eax
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; CHECK-NEXT: shrl $9, %eax
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; CHECK-NEXT: ret
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}
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define signext i16 @test4(i16 signext %x) nounwind {
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entry:
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%div = sdiv i16 %x, 33 ; <i32> [#uses=1]
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ret i16 %div
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; CHECK: test4:
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; CHECK: imull $1986, %eax, %eax
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}
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define i32 @test5(i32 %A) nounwind {
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%tmp1 = udiv i32 %A, 1577682821 ; <i32> [#uses=1]
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ret i32 %tmp1
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; CHECK: test5:
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; CHECK: movl $365384439, %eax
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; CHECK: mull 4(%esp)
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}
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define signext i16 @test6(i16 signext %x) nounwind {
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entry:
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%div = sdiv i16 %x, 10
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ret i16 %div
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; CHECK: test6:
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; CHECK: imull $26215, %eax, %eax
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; CHECK: shrl $31, %ecx
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; CHECK: sarl $18, %eax
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}
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