mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-09-01 19:29:22 +00:00
247c5ab07c
This patch will optimize the following cases: sub r1, r3 | sub r1, imm cmp r3, r1 or cmp r1, r3 | cmp r1, imm bge L1 TO subs r1, r3 bge L1 or ble L1 If the branch instruction can use flag from "sub", then we can replace "sub" with "subs" and eliminate the "cmp" instruction. rdar: 10734411 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156599 91177308-0d34-0410-b5e6-96231b3b80d8
35 lines
695 B
LLVM
35 lines
695 B
LLVM
; RUN: llc < %s -mtriple=arm-apple-darwin | FileCheck %s
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define i32 @f(i32 %a, i32 %b) nounwind ssp {
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entry:
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; CHECK: f:
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; CHECK: subs
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; CHECK-NOT: cmp
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%cmp = icmp sgt i32 %a, %b
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%sub = sub nsw i32 %a, %b
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%sub. = select i1 %cmp, i32 %sub, i32 0
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ret i32 %sub.
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}
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define i32 @g(i32 %a, i32 %b) nounwind ssp {
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entry:
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; CHECK: g:
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; CHECK: subs
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; CHECK-NOT: cmp
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%cmp = icmp slt i32 %a, %b
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%sub = sub nsw i32 %b, %a
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%sub. = select i1 %cmp, i32 %sub, i32 0
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ret i32 %sub.
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}
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define i32 @h(i32 %a, i32 %b) nounwind ssp {
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entry:
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; CHECK: h:
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; CHECK: subs
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; CHECK-NOT: cmp
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%cmp = icmp sgt i32 %a, 3
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%sub = sub nsw i32 %a, 3
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%sub. = select i1 %cmp, i32 %sub, i32 %b
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ret i32 %sub.
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}
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