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https://github.com/RPCSX/llvm.git
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1a63641597
Summary: Previously it only avoided optimizing signed comparisons to 0. Sometimes the DAGCombiner will optimize the unsigned comparisons to 0 before it gets to the peephole pass, but sometimes it doesn't. Fix for PR22373. Test Plan: test/CodeGen/ARM/sub-cmp-peephole.ll Reviewers: jfb, manmanren Subscribers: aemerson, llvm-commits Differential Revision: http://reviews.llvm.org/D7274 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227809 91177308-0d34-0410-b5e6-96231b3b80d8
207 lines
4.6 KiB
LLVM
207 lines
4.6 KiB
LLVM
; RUN: llc < %s -mtriple=arm-apple-darwin | FileCheck %s
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; RUN: llc < %s -mtriple=arm-apple-darwin | FileCheck %s --check-prefix=V7
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; RUN: llc < %s -mtriple=armv8-none-linux-gnueabi | FileCheck %s -check-prefix=V8
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define i32 @f(i32 %a, i32 %b) nounwind ssp {
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entry:
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; CHECK-LABEL: 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-LABEL: 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-LABEL: 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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; rdar://11725965
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define i32 @i(i32 %a, i32 %b) nounwind readnone ssp {
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entry:
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; CHECK-LABEL: i:
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; CHECK: subs
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; CHECK-NOT: cmp
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%cmp = icmp ult i32 %a, %b
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%sub = sub 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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; If CPSR is live-out, we can't remove cmp if there exists
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; a swapped sub.
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define i32 @j(i32 %a, i32 %b) nounwind {
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entry:
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; CHECK-LABEL: j:
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; CHECK: sub
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; CHECK: cmp
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%cmp = icmp eq i32 %b, %a
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%sub = sub nsw i32 %a, %b
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br i1 %cmp, label %if.then, label %if.else
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if.then:
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%cmp2 = icmp sgt i32 %b, %a
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%sel = select i1 %cmp2, i32 %sub, i32 %a
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ret i32 %sel
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if.else:
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ret i32 %sub
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}
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; If the sub/rsb instruction is predicated, we can't use the flags.
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; <rdar://problem/12263428>
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; Test case from MultiSource/Benchmarks/Ptrdist/bc/number.s
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; CHECK: bc_raise
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; CHECK: rsbeq
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; CHECK: cmp
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define i32 @bc_raise() nounwind ssp {
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entry:
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%val.2.i = select i1 undef, i32 0, i32 undef
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%sub.i = sub nsw i32 0, %val.2.i
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%retval.0.i = select i1 undef, i32 %val.2.i, i32 %sub.i
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%cmp1 = icmp eq i32 %retval.0.i, 0
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br i1 %cmp1, label %land.lhs.true, label %if.end11
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land.lhs.true: ; preds = %num2long.exit
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ret i32 17
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if.end11: ; preds = %num2long.exit
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ret i32 23
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}
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; When considering the producer of cmp's src as the subsuming instruction,
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; only consider that when the comparison is to 0.
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define i32 @cmp_src_nonzero(i32 %a, i32 %b, i32 %x, i32 %y) {
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entry:
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; CHECK-LABEL: cmp_src_nonzero:
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; CHECK: sub
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; CHECK: cmp
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%sub = sub i32 %a, %b
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%cmp = icmp eq i32 %sub, 17
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%ret = select i1 %cmp, i32 %x, i32 %y
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ret i32 %ret
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}
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define float @float_sel(i32 %a, i32 %b, float %x, float %y) {
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entry:
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; CHECK-LABEL: float_sel:
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; CHECK-NOT: cmp
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; V8-LABEL: float_sel:
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; V8-NOT: cmp
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; V8: vseleq.f32
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%sub = sub i32 %a, %b
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%cmp = icmp eq i32 %sub, 0
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%ret = select i1 %cmp, float %x, float %y
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ret float %ret
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}
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define double @double_sel(i32 %a, i32 %b, double %x, double %y) {
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entry:
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; CHECK-LABEL: double_sel:
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; CHECK-NOT: cmp
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; V8-LABEL: double_sel:
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; V8-NOT: cmp
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; V8: vseleq.f64
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%sub = sub i32 %a, %b
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%cmp = icmp eq i32 %sub, 0
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%ret = select i1 %cmp, double %x, double %y
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ret double %ret
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}
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@t = common global i32 0
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define double @double_sub(i32 %a, i32 %b, double %x, double %y) {
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entry:
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; CHECK-LABEL: double_sub:
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; CHECK: subs
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; CHECK-NOT: cmp
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; V8-LABEL: double_sub:
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; V8: vsel
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%cmp = icmp sgt i32 %a, %b
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%sub = sub i32 %a, %b
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store i32 %sub, i32* @t
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%ret = select i1 %cmp, double %x, double %y
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ret double %ret
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}
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define double @double_sub_swap(i32 %a, i32 %b, double %x, double %y) {
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entry:
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; V7-LABEL: double_sub_swap:
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; V7-NOT: cmp
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; V7: subs
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; V8-LABEL: double_sub_swap:
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; V8-NOT: subs
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; V8: cmp
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; V8: vsel
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%cmp = icmp sgt i32 %a, %b
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%sub = sub i32 %b, %a
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%ret = select i1 %cmp, double %x, double %y
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store i32 %sub, i32* @t
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ret double %ret
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}
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declare void @abort()
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declare void @exit(i32)
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; If the comparison uses the V bit (signed overflow/underflow), we can't
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; omit the comparison.
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define i32 @cmp_slt0(i32 %a, i32 %b, i32 %x, i32 %y) {
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entry:
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; CHECK-LABEL: cmp_slt0
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; CHECK: sub
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; CHECK: cmp
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; CHECK: bge
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%load = load i32* @t, align 4
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%sub = sub i32 %load, 17
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%cmp = icmp slt i32 %sub, 0
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br i1 %cmp, label %if.then, label %if.else
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if.then:
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call void @abort()
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unreachable
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if.else:
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call void @exit(i32 0)
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unreachable
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}
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; Same for the C bit. (Note the ult X, 0 is trivially
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; false, so the DAG combiner may or may not optimize it).
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define i32 @cmp_ult0(i32 %a, i32 %b, i32 %x, i32 %y) {
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entry:
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; CHECK-LABEL: cmp_ult0
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; CHECK: sub
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; CHECK: cmp
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; CHECK: bhs
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%load = load i32* @t, align 4
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%sub = sub i32 %load, 17
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%cmp = icmp ult i32 %sub, 0
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br i1 %cmp, label %if.then, label %if.else
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if.then:
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call void @abort()
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unreachable
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if.else:
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call void @exit(i32 0)
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unreachable
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}
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