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llvm-mirror/test/CodeGen/PowerPC/setcr_bc2.mir
Hiroshi Inoue a1abfc12f3 [PowerPC] optimize conditional branch on CRSET/CRUNSET
This patch adds a check to optimize conditional branch (BC and BCn) based on a constant set by CRSET or CRUNSET.
Other optimizers, such as block placement, may generate such code and hence
I do this at the very end of the optimization in pre-emit peephole pass.

A conditional branch based on a constant is eliminated or converted into unconditional branch. 
Also CRSET/CRUNSET is eliminated if the condition code register is not used
by instruction other than the branch to be optimized.

Differential Revision: https://reviews.llvm.org/D52345

llvm-svn: 343100
2018-09-26 12:32:45 +00:00

133 lines
5.2 KiB
YAML

# RUN: llc -verify-machineinstrs -start-before=ppc-pre-emit-peephole %s -o - | FileCheck %s
--- |
target datalayout = "e-m:e-i64:64-n32:64"
target triple = "powerpc64le-unknown-linux-gnu"
declare signext i32 @callee(i32 signext) local_unnamed_addr #1
define signext i32 @func(i32 signext %v) local_unnamed_addr #0 {
entry:
%call.i = tail call signext i32 @callee(i32 signext %v)
%tobool.i = icmp eq i32 %call.i, 0
br i1 %tobool.i, label %if.else.i, label %if.then.i
if.then.i: ; preds = %entry
%call2.i = tail call signext i32 @callee(i32 signext %call.i)
br label %_Z6calleei.exit
if.else.i: ; preds = %entry
%phitmp = icmp sgt i32 %v, -1
br label %_Z6calleei.exit
_Z6calleei.exit: ; preds = %if.else.i, %if.then.i
%call2.i.sink = phi i32 [ %call2.i, %if.then.i ], [ %v, %if.else.i ]
%.sink = phi i1 [ false, %if.then.i ], [ %phitmp, %if.else.i ]
br i1 %.sink, label %if.end, label %if.then
if.then: ; preds = %_Z6calleei.exit
%call1 = tail call signext i32 @callee(i32 signext 0)
br label %if.end
if.end: ; preds = %if.then, %_Z6calleei.exit
ret i32 %call2.i.sink
}
attributes #0 = { "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="ppc64le" "target-features"="+altivec,+bpermd,+crypto,+direct-move,+extdiv,+htm,+power8-vector,+vsx,-power9-vector,-qpx" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="ppc64le" "target-features"="+altivec,+bpermd,+crypto,+direct-move,+extdiv,+htm,+power8-vector,+vsx,-power9-vector,-qpx" "unsafe-fp-math"="false" "use-soft-float"="false" }
...
---
name: func
alignment: 4
exposesReturnsTwice: false
legalized: false
regBankSelected: false
selected: false
failedISel: false
tracksRegLiveness: true
registers:
liveins:
- { reg: '$x3', virtual-reg: '' }
frameInfo:
isFrameAddressTaken: false
isReturnAddressTaken: false
hasStackMap: false
hasPatchPoint: false
stackSize: 48
offsetAdjustment: 0
maxAlignment: 0
adjustsStack: true
hasCalls: true
stackProtector: ''
maxCallFrameSize: 32
hasOpaqueSPAdjustment: false
hasVAStart: false
hasMustTailInVarArgFunc: false
localFrameSize: 0
savePoint: ''
restorePoint: ''
fixedStack:
- { id: 0, type: spill-slot, offset: -16, size: 8, alignment: 16, stack-id: 0,
callee-saved-register: '$x30', callee-saved-restored: true, debug-info-variable: '',
debug-info-expression: '', debug-info-location: '' }
stack:
constants:
body: |
bb.0.entry:
successors: %bb.2(0x30000000), %bb.1(0x50000000)
liveins: $x3, $x30
; bc should be converted into b, but creqv (CRSET) should not be removed since it is used in a predecessor.
; CHECK-LABEL: func
; CHECK: # %bb.1
; CHECK: creqv
; CHECK-NOT: bc
; CHECK: .LBB0_2
$x0 = MFLR8 implicit $lr8
STD killed $x0, 16, $x1
$x1 = STDU $x1, -48, $x1
STD killed $x30, 32, $x1 :: (store 8 into %fixed-stack.0, align 16)
$x30 = OR8 $x3, $x3
BL8_NOP @callee, csr_svr464_altivec, implicit-def dead $lr8, implicit $rm, implicit killed $x3, implicit $x2, implicit-def $r1, implicit-def $x3
renamable $cr0 = CMPLWI renamable $r3, 0
BCC 76, killed renamable $cr0, %bb.2
bb.1.if.then.i:
successors: %bb.5(0x40000000), %bb.4(0x40000000)
liveins: $x3
renamable $x3 = EXTSW_32_64 killed renamable $r3, implicit $x3
BL8_NOP @callee, csr_svr464_altivec, implicit-def dead $lr8, implicit $rm, implicit killed $x3, implicit $x2, implicit-def $r1, implicit-def $x3
renamable $cr0gt = CRSET implicit-def $cr0
$x30 = OR8 killed $x3, $x3
BC killed renamable $cr0gt, %bb.5
bb.4.if.then:
successors: %bb.5(0x80000000)
liveins: $x30
$x3 = LI8 0
BL8_NOP @callee, csr_svr464_altivec, implicit-def dead $lr8, implicit $rm, implicit killed $x3, implicit $x2, implicit-def $r1, implicit-def dead $x3
bb.5.if.end:
liveins: $x30, $cr0gt
renamable $x3 = EXTSW_32_64 killed renamable $r30, implicit $x30
$x30 = LD 32, $x1 :: (load 8 from %fixed-stack.0, align 16)
$x1 = ADDI8 $x1, 48
$x0 = LD 16, $x1
MTLR8 killed $x0, implicit-def $lr8
BLR8 implicit $lr8, implicit $rm, implicit killed $x3
bb.2.if.else.i:
successors: %bb.5(0x40000000), %bb.4(0x40000000)
liveins: $x30
renamable $cr0 = CMPWI renamable $r30, -1
BCn killed renamable $cr0gt, %bb.4
B %bb.5
...