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llvm-mirror/test/CodeGen/PowerPC/no-rlwimi-trivial-commute.mir
Hal Finkel 2e0ee83cd9 [PowerPC] Don't commute trivial rlwimi instructions
To commute a trivial rlwimi instructions (meaning one with a full mask and zero
shift), we'd need to ability to form an all-zero mask (instead of an all-one
mask) using rlwimi. We can't represent this, however, and we'll miscompile code
if we try.

The code quality problem that this highlights (that SDAG simplification can
lead to us generating an ISD::OR node with a constant zero LHS) will be fixed
as a follow-up.

Fixes PR24719.

llvm-svn: 246937
2015-09-06 04:17:30 +00:00

93 lines
2.6 KiB
YAML

# RUN: llc -start-after=dead-mi-elimination -stop-after=twoaddressinstruction -o /dev/null %s | FileCheck %s
--- |
target datalayout = "E-m:e-i64:64-n32:64"
target triple = "powerpc64-unknown-linux-gnu"
@d = global i32 15, align 4
@b = global i32* @d, align 8
@a = common global i32 0, align 4
; Function Attrs: nounwind
define signext i32 @main() #0 {
entry:
%0 = load i32*, i32** @b, align 8
%1 = load i32, i32* @a, align 4
%lnot = icmp eq i32 %1, 0
%lnot.ext = zext i1 %lnot to i32
%shr.i = lshr i32 2072, %lnot.ext
%call.lobit = lshr i32 %shr.i, 7
%2 = and i32 %call.lobit, 1
%3 = load i32, i32* %0, align 4
%or = or i32 %2, %3
store i32 %or, i32* %0, align 4
%4 = load i32, i32* @a, align 4
%lnot.1 = icmp eq i32 %4, 0
%lnot.ext.1 = zext i1 %lnot.1 to i32
%shr.i.1 = lshr i32 2072, %lnot.ext.1
%call.lobit.1 = lshr i32 %shr.i.1, 7
%5 = and i32 %call.lobit.1, 1
%or.1 = or i32 %5, %or
store i32 %or.1, i32* %0, align 4
ret i32 %or.1
}
attributes #0 = { nounwind "target-cpu"="ppc64" }
...
---
name: main
alignment: 2
exposesReturnsTwice: false
hasInlineAsm: false
isSSA: true
tracksRegLiveness: true
tracksSubRegLiveness: false
registers:
- { id: 0, class: g8rc_and_g8rc_nox0 }
- { id: 1, class: g8rc_and_g8rc_nox0 }
- { id: 2, class: gprc }
- { id: 3, class: gprc }
- { id: 4, class: gprc }
- { id: 5, class: g8rc_and_g8rc_nox0 }
- { id: 6, class: g8rc_and_g8rc_nox0 }
- { id: 7, class: gprc }
- { id: 8, class: gprc }
- { id: 9, class: gprc }
- { id: 10, class: g8rc }
frameInfo:
isFrameAddressTaken: false
isReturnAddressTaken: false
hasStackMap: false
hasPatchPoint: false
stackSize: 0
offsetAdjustment: 0
maxAlignment: 0
adjustsStack: false
hasCalls: false
maxCallFrameSize: 0
hasOpaqueSPAdjustment: false
hasVAStart: false
hasMustTailInVarArgFunc: false
body: |
bb.0.entry:
liveins: %x2
%0 = ADDIStocHA %x2, @b
%1 = LD target-flags(ppc-toc-lo) @b, killed %0 :: (load 8 from @b)
%2 = LWZ 0, %1 :: (load 4 from %ir.0)
%3 = LI 0
%4 = RLWIMI %3, killed %2, 0, 0, 31
; CHECK-LABEL: name: main
; CHECK: %[[REG1:[0-9]+]] = LI 0
; CHECK: %[[REG2:[0-9]+]] = COPY %[[REG1]]
; CHECK: %[[REG2]] = RLWIMI %[[REG2]], killed %2, 0, 0, 31
%8 = RLWIMI %3, %4, 0, 0, 31
STW %4, 0, %1 :: (store 4 into %ir.0)
%10 = EXTSW_32_64 %8
STW %8, 0, %1 :: (store 4 into %ir.0)
%x3 = COPY %10
BLR8 implicit %x3, implicit %lr8, implicit %rm
...