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33474b29b1
Summary: Optimize code generated for variable shifts/rotates by taking advantage of the implicit and/mod done on the variable shift amount register. Resolves bug 27582 and bug 37421. Reviewers: t.p.northover, qcolombet, MatzeB, javed.absar Subscribers: rengolin, kristof.beyls, mcrosier, llvm-commits Differential Revision: https://reviews.llvm.org/D46844 llvm-svn: 333214
35 lines
830 B
LLVM
35 lines
830 B
LLVM
; RUN: llc -mtriple=aarch64 < %s | FileCheck %s
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; Check that we optimize out AND instructions and ADD/SUB instructions
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; modulo the shift size to take advantage of the implicit mod done on
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; the shift amount value by the variable shift/rotate instructions.
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define i32 @test1(i32 %x, i64 %y) {
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; CHECK-LABEL: test1:
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; CHECK-NOT: and
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; CHECK: lsr
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%sh_prom = trunc i64 %y to i32
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%shr = lshr i32 %x, %sh_prom
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ret i32 %shr
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}
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define i64 @test2(i32 %x, i64 %y) {
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; CHECK-LABEL: test2:
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; CHECK-NOT: orr
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; CHECK-NOT: sub
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; CHECK: neg
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; CHECK: asr
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%sub9 = sub nsw i32 64, %x
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%sh_prom12.i = zext i32 %sub9 to i64
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%shr.i = ashr i64 %y, %sh_prom12.i
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ret i64 %shr.i
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}
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define i64 @test3(i64 %x, i64 %y) {
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; CHECK-LABEL: test3:
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; CHECK-NOT: add
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; CHECK: lsl
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%add = add nsw i64 64, %x
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%shl = shl i64 %y, %add
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ret i64 %shl
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} |