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[X86][AVX] Fix failure due to a missing ISel pattern to select VBROADCAST nodes (PR23259). 

This fixes a regression introduced at revision 218263.

On AVX, if we optimize for size, a splat build_vector of a load
is lowered into a VBROADCAST node. This is done even if the value type of the
splat build_vector node is v2i64.

Since AVX doesn't support v2f64/v2i64 broadcasts, revision 218263 added two
extra tablegen patterns to allow selecting a VMOVDDUPrm from an X86VBroadcast
where the scalar element comes from a loadi64/loadf64.

However, revision 218263 forgot to add an extra fallback pattern for the case
where we have a X86VBroadcast of a loadi64 with multiple uses.

This patch adds the missing tablegen pattern in X86InstrSSE.td.
This patch also adds an extra test to 'splat-for-size.ll' to verify that ISel
doesn't crash with a 'fatal error in the backend' due to a missing AVX pattern
to select v2i64 X86ISD::BROADCAST nodes.

llvm-svn: 235509
This commit is contained in:
Andrea Di Biagio 2015-04-22 14:53:39 +00:00
parent c587bee405
commit 6cd2f42fac
2 changed files with 18 additions and 2 deletions
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6
llvm/lib/Target/X86/X86InstrSSE.td
View File

@ -5223,9 +5223,9 @@ let Predicates = [HasAVX] in {
let Predicates = [UseAVX, OptForSize] in {
def : Pat<(v2f64 (X86VBroadcast (loadf64 addr:$src))),
(VMOVDDUPrm addr:$src)>;
(VMOVDDUPrm addr:$src)>;
def : Pat<(v2i64 (X86VBroadcast (loadi64 addr:$src))),
(VMOVDDUPrm addr:$src)>;
(VMOVDDUPrm addr:$src)>;
}
let Predicates = [UseSSE3] in {
@ -8478,6 +8478,8 @@ let Predicates = [HasAVX] in {
def : Pat<(v2f64 (X86VBroadcast f64:$src)),
(VMOVDDUPrr (COPY_TO_REGCLASS FR64:$src, VR128))>;
def : Pat<(v2i64 (X86VBroadcast i64:$src)),
(VMOVDDUPrr (COPY_TO_REGCLASS GR64:$src, VR128))>;
}
//===----------------------------------------------------------------------===//

14
llvm/test/CodeGen/X86/splat-for-size.ll
View File

@ -138,4 +138,18 @@ define <32 x i8> @splat_v32i8(<32 x i8> %x) #0 {
; CHECK: retq
}
; PR23259: Verify that ISel doesn't crash with a 'fatal error in backend'
; due to a missing AVX pattern to select a v2i64 X86ISD::BROADCAST of a
; loadi16 with multiple uses.
@A = common global <3 x i64> zeroinitializer, align 32
define <8 x i64> @pr23259() #0 {
entry:
%0 = load <4 x i64>, <4 x i64>* bitcast (<3 x i64>* @A to <4 x i64>*), align 32
%1 = shufflevector <4 x i64> %0, <4 x i64> undef, <3 x i32> <i32 undef, i32 undef, i32 2>
%shuffle = shufflevector <3 x i64> <i64 1, i64 undef, i64 undef>, <3 x i64> %1, <8 x i32> <i32 5, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0>
ret <8 x i64> %shuffle
}
attributes #0 = { optsize }