[PATCH] D25039: [X86][AVX] Ensure broadcast loads respect dependencies
Simon Pilgrim via llvm-commits
llvm-commits at lists.llvm.org
Tue Oct 4 01:04:19 PDT 2016
This revision was automatically updated to reflect the committed changes.
Closed by commit rL283070: [X86][AVX] Ensure broadcast loads respect dependencies (authored by RKSimon).
Changed prior to commit:
https://reviews.llvm.org/D25039?vs=72877&id=73404#toc
Repository:
rL LLVM
https://reviews.llvm.org/D25039
Files:
llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
llvm/trunk/test/CodeGen/X86/avx-vbroadcast.ll
Index: llvm/trunk/test/CodeGen/X86/avx-vbroadcast.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/avx-vbroadcast.ll
+++ llvm/trunk/test/CodeGen/X86/avx-vbroadcast.ll
@@ -548,38 +548,40 @@
}
;
-; FIXME: When VBROADCAST replaces an existing load, ensure it still respects lifetime dependencies.
+; When VBROADCAST replaces an existing load, ensure it still respects lifetime dependencies.
;
define float @broadcast_lifetime() nounwind {
; X32-LABEL: broadcast_lifetime:
; X32: ## BB#0:
; X32-NEXT: pushl %esi
-; X32-NEXT: subl $40, %esp
+; X32-NEXT: subl $56, %esp
; X32-NEXT: leal {{[0-9]+}}(%esp), %esi
; X32-NEXT: movl %esi, (%esp)
; X32-NEXT: calll _gfunc
+; X32-NEXT: vbroadcastss {{[0-9]+}}(%esp), %xmm0
+; X32-NEXT: vmovaps %xmm0, {{[0-9]+}}(%esp) ## 16-byte Spill
; X32-NEXT: movl %esi, (%esp)
; X32-NEXT: calll _gfunc
; X32-NEXT: vbroadcastss {{[0-9]+}}(%esp), %xmm0
-; X32-NEXT: vbroadcastss {{[0-9]+}}(%esp), %xmm1
-; X32-NEXT: vsubss %xmm0, %xmm1, %xmm0
+; X32-NEXT: vsubss {{[0-9]+}}(%esp), %xmm0, %xmm0 ## 16-byte Folded Reload
; X32-NEXT: vmovss %xmm0, {{[0-9]+}}(%esp)
; X32-NEXT: flds {{[0-9]+}}(%esp)
-; X32-NEXT: addl $40, %esp
+; X32-NEXT: addl $56, %esp
; X32-NEXT: popl %esi
; X32-NEXT: retl
;
; X64-LABEL: broadcast_lifetime:
; X64: ## BB#0:
-; X64-NEXT: subq $24, %rsp
+; X64-NEXT: subq $40, %rsp
; X64-NEXT: movq %rsp, %rdi
; X64-NEXT: callq _gfunc
+; X64-NEXT: vbroadcastss {{[0-9]+}}(%rsp), %xmm0
+; X64-NEXT: vmovaps %xmm0, {{[0-9]+}}(%rsp) ## 16-byte Spill
; X64-NEXT: movq %rsp, %rdi
; X64-NEXT: callq _gfunc
; X64-NEXT: vbroadcastss {{[0-9]+}}(%rsp), %xmm0
-; X64-NEXT: vbroadcastss {{[0-9]+}}(%rsp), %xmm1
-; X64-NEXT: vsubss %xmm0, %xmm1, %xmm0
-; X64-NEXT: addq $24, %rsp
+; X64-NEXT: vsubss {{[0-9]+}}(%rsp), %xmm0, %xmm0 ## 16-byte Folded Reload
+; X64-NEXT: addq $40, %rsp
; X64-NEXT: retq
%1 = alloca <4 x float>, align 16
%2 = alloca <4 x float>, align 16
Index: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
@@ -8683,6 +8683,17 @@
V = DAG.getLoad(SVT, DL, Ld->getChain(), NewAddr,
DAG.getMachineFunction().getMachineMemOperand(
Ld->getMemOperand(), Offset, SVT.getStoreSize()));
+
+ // Make sure the newly-created LOAD is in the same position as Ld in
+ // terms of dependency. We create a TokenFactor for Ld and V,
+ // and update uses of Ld's output chain to use the TokenFactor.
+ if (Ld->hasAnyUseOfValue(1)) {
+ SDValue NewChain = DAG.getNode(ISD::TokenFactor, DL, MVT::Other,
+ SDValue(Ld, 1), SDValue(V.getNode(), 1));
+ DAG.ReplaceAllUsesOfValueWith(SDValue(Ld, 1), NewChain);
+ DAG.UpdateNodeOperands(NewChain.getNode(), SDValue(Ld, 1),
+ SDValue(V.getNode(), 1));
+ }
} else if (!BroadcastFromReg) {
// We can't broadcast from a vector register.
return SDValue();
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