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llvm-mirror/test/CodeGen/ARM/sub-cmp-peephole.ll
Eli Friedman 9ae1cdf437 [ARM] Treat cmn immediates as legal in isLegalICmpImmediate.
The original code attempted to do this, but the std::abs() call didn't
actually do anything due to implicit type conversions.  Fix the type
conversions, and perform the correct check for negative immediates.

This probably has very little practical impact, but it's worth fixing
just to avoid confusion in the future, I think.

Differential Revision: https://reviews.llvm.org/D48907

llvm-svn: 336742
2018-07-10 23:44:37 +00:00

207 lines
4.7 KiB
LLVM

; RUN: llc < %s -mtriple=arm-apple-darwin | FileCheck %s
; RUN: llc < %s -mtriple=arm-apple-darwin | FileCheck %s --check-prefix=V7
; RUN: llc < %s -mtriple=armv8-none-linux-gnueabi | FileCheck %s -check-prefix=V8
define i32 @f(i32 %a, i32 %b) nounwind ssp {
entry:
; CHECK-LABEL: f:
; CHECK: subs
; CHECK-NOT: cmp
%cmp = icmp sgt i32 %a, %b
%sub = sub nsw i32 %a, %b
%sub. = select i1 %cmp, i32 %sub, i32 0
ret i32 %sub.
}
define i32 @g(i32 %a, i32 %b) nounwind ssp {
entry:
; CHECK-LABEL: g:
; CHECK: subs
; CHECK-NOT: cmp
%cmp = icmp slt i32 %a, %b
%sub = sub nsw i32 %b, %a
%sub. = select i1 %cmp, i32 %sub, i32 0
ret i32 %sub.
}
define i32 @h(i32 %a, i32 %b) nounwind ssp {
entry:
; CHECK-LABEL: h:
; CHECK: subs
; CHECK-NOT: cmp
%cmp = icmp sgt i32 %a, 3
%sub = sub nsw i32 %a, 3
%sub. = select i1 %cmp, i32 %sub, i32 %b
ret i32 %sub.
}
; rdar://11725965
define i32 @i(i32 %a, i32 %b) nounwind readnone ssp {
entry:
; CHECK-LABEL: i:
; CHECK: subs
; CHECK-NOT: cmp
%cmp = icmp ult i32 %a, %b
%sub = sub i32 %b, %a
%sub. = select i1 %cmp, i32 %sub, i32 0
ret i32 %sub.
}
; If CPSR is live-out, we can't remove cmp if there exists
; a swapped sub.
define i32 @j(i32 %a, i32 %b) nounwind {
entry:
; CHECK-LABEL: j:
; CHECK: sub
; CHECK: cmp
%cmp = icmp eq i32 %b, %a
%sub = sub nsw i32 %a, %b
br i1 %cmp, label %if.then, label %if.else
if.then:
%cmp2 = icmp sgt i32 %b, %a
%sel = select i1 %cmp2, i32 %sub, i32 %a
ret i32 %sel
if.else:
ret i32 %sub
}
; If the sub/rsb instruction is predicated, we can't use the flags.
; <rdar://problem/12263428>
; Test case from MultiSource/Benchmarks/Ptrdist/bc/number.s
; CHECK: bc_raise
; CHECK: rsbeq
; CHECK: cmp
define i32 @bc_raise(i1 %cond) nounwind ssp {
entry:
%val.2.i = select i1 %cond, i32 0, i32 undef
%sub.i = sub nsw i32 0, %val.2.i
%retval.0.i = select i1 %cond, i32 %val.2.i, i32 %sub.i
%cmp1 = icmp eq i32 %retval.0.i, 0
br i1 %cmp1, label %land.lhs.true, label %if.end11
land.lhs.true: ; preds = %num2long.exit
ret i32 17
if.end11: ; preds = %num2long.exit
ret i32 23
}
; When considering the producer of cmp's src as the subsuming instruction,
; only consider that when the comparison is to 0.
define i32 @cmp_src_nonzero(i32 %a, i32 %b, i32 %x, i32 %y) {
entry:
; CHECK-LABEL: cmp_src_nonzero:
; CHECK: sub
; CHECK: cmp
%sub = sub i32 %a, %b
%cmp = icmp eq i32 %sub, 17
%ret = select i1 %cmp, i32 %x, i32 %y
ret i32 %ret
}
define float @float_sel(i32 %a, i32 %b, float %x, float %y) {
entry:
; CHECK-LABEL: float_sel:
; CHECK-NOT: cmp
; V8-LABEL: float_sel:
; V8-NOT: cmp
; V8: vseleq.f32
%sub = sub i32 %a, %b
%cmp = icmp eq i32 %sub, 0
%ret = select i1 %cmp, float %x, float %y
ret float %ret
}
define double @double_sel(i32 %a, i32 %b, double %x, double %y) {
entry:
; CHECK-LABEL: double_sel:
; CHECK-NOT: cmp
; V8-LABEL: double_sel:
; V8-NOT: cmp
; V8: vseleq.f64
%sub = sub i32 %a, %b
%cmp = icmp eq i32 %sub, 0
%ret = select i1 %cmp, double %x, double %y
ret double %ret
}
@t = common global i32 0
define double @double_sub(i32 %a, i32 %b, double %x, double %y) {
entry:
; CHECK-LABEL: double_sub:
; CHECK: subs
; CHECK-NOT: cmp
; V8-LABEL: double_sub:
; V8: vsel
%cmp = icmp sgt i32 %a, %b
%sub = sub i32 %a, %b
store i32 %sub, i32* @t
%ret = select i1 %cmp, double %x, double %y
ret double %ret
}
define double @double_sub_swap(i32 %a, i32 %b, double %x, double %y) {
entry:
; V7-LABEL: double_sub_swap:
; V7-NOT: cmp
; V7: subs
; V8-LABEL: double_sub_swap:
; V8-NOT: subs
; V8: cmp
; V8: vsel
%cmp = icmp sgt i32 %a, %b
%sub = sub i32 %b, %a
%ret = select i1 %cmp, double %x, double %y
store i32 %sub, i32* @t
ret double %ret
}
declare void @abort()
declare void @exit(i32)
; If the comparison uses the V bit (signed overflow/underflow), we can't
; omit the comparison.
define i32 @cmp_slt0(i32 %a, i32 %b, i32 %x, i32 %y) {
entry:
; CHECK-LABEL: cmp_slt0
; CHECK: sub
; CHECK: cmn
; CHECK: bgt
%load = load i32, i32* @t, align 4
%sub = sub i32 %load, 17
%cmp = icmp slt i32 %sub, 0
br i1 %cmp, label %if.then, label %if.else
if.then:
call void @abort()
unreachable
if.else:
call void @exit(i32 0)
unreachable
}
; Same for the C bit. (Note the ult X, 0 is trivially
; false, so the DAG combiner may or may not optimize it).
define i32 @cmp_ult0(i32 %a, i32 %b, i32 %x, i32 %y) {
entry:
; CHECK-LABEL: cmp_ult0
; CHECK: sub
; CHECK: cmp
; CHECK: bhs
%load = load i32, i32* @t, align 4
%sub = sub i32 %load, 17
%cmp = icmp ult i32 %sub, 0
br i1 %cmp, label %if.then, label %if.else
if.then:
call void @abort()
unreachable
if.else:
call void @exit(i32 0)
unreachable
}