mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-22 23:31:32 +00:00
519daf5d2d
The ARM backend can eliminate cmp instructions by reusing flags from a nearby sub instruction with similar arguments. Don't do that if the sub is predicated - the flags are not written unconditionally. <rdar://problem/12263428> git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163535 91177308-0d34-0410-b5e6-96231b3b80d8
87 lines
1.9 KiB
LLVM
87 lines
1.9 KiB
LLVM
; RUN: llc < %s -mtriple=arm-apple-darwin | FileCheck %s
|
|
|
|
define i32 @f(i32 %a, i32 %b) nounwind ssp {
|
|
entry:
|
|
; CHECK: 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: 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: 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: 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: 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() nounwind ssp {
|
|
entry:
|
|
%val.2.i = select i1 undef, i32 0, i32 undef
|
|
%sub.i = sub nsw i32 0, %val.2.i
|
|
%retval.0.i = select i1 undef, 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
|
|
}
|