llvm/test/CodeGen/ARM/2010-06-29-PartialRedefFastAlloc.ll
Jakob Stoklund Olesen d36f5af224 Set correct <def,undef> flags when lowering REG_SEQUENCE.
A REG_SEQUENCE instruction is lowered into a sequence of partial defs:

  %vreg7:ssub_0<def,undef> = COPY %vreg20:ssub_0
  %vreg7:ssub_1<def> = COPY %vreg2
  %vreg7:ssub_2<def> = COPY %vreg2
  %vreg7:ssub_3<def> = COPY %vreg2

The first def needs an <undef> flag to indicate it is the beginning of
the live range, while the other defs are read-modify-write.  Previously,
we depended on LiveIntervalAnalysis to notice and fix the missing
<def,undef>, but that solution was never robust, it was causing problems
with ProcessImplicitDefs and the lowering of chained REG_SEQUENCE
instructions.

This fixes PR11841.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148879 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-24 23:28:42 +00:00

26 lines
956 B
LLVM

; RUN: llc < %s -O0 -mcpu=cortex-a8 | FileCheck %s
target datalayout = "e-p:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:32:32-f32:32:32-f64:32:32-v64:32:64-v128:32:128-a0:0:32-n32"
target triple = "thumbv7-apple-darwin10"
; This tests the fast register allocator's handling of partial redefines:
;
; %reg1028:dsub_0<def>, %reg1028:dsub_1<def> = VLD1q64 %reg1025...
; %reg1030:dsub_1<def> = COPY %reg1028:dsub_0<kill>
;
; %reg1028 gets allocated %Q0, and if %reg1030 is reloaded for the partial
; redef, it cannot also get %Q0.
; CHECK: vld1.64 {d16, d17}, [r{{.}}]
; CHECK-NOT: vld1.64 {d16, d17}
; CHECK: vmov.f64
define i32 @test(i8* %arg) nounwind {
entry:
%0 = call <2 x i64> @llvm.arm.neon.vld1.v2i64(i8* %arg, i32 1)
%1 = shufflevector <2 x i64> undef, <2 x i64> %0, <2 x i32> <i32 1, i32 2>
store <2 x i64> %1, <2 x i64>* undef, align 16
ret i32 undef
}
declare <2 x i64> @llvm.arm.neon.vld1.v2i64(i8*, i32) nounwind readonly