[PATCH] D32755: [DAGCombine] (addcarry (add|uaddo X, Y), 0, Carry) -> (addcarry X, Y, Carry)
Amaury SECHET via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Wed May 3 09:41:26 PDT 2017
This revision was automatically updated to reflect the committed changes.
Closed by commit rL302047: [DAGCombine] (addcarry (add|uaddo X, Y), 0, Carry) -> (addcarry X, Y, Carry) (authored by deadalnix).
Changed prior to commit:
https://reviews.llvm.org/D32755?vs=97670&id=97671#toc
Repository:
rL LLVM
https://reviews.llvm.org/D32755
Files:
llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
llvm/trunk/test/CodeGen/X86/addcarry.ll
Index: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -242,6 +242,7 @@
SDValue visitUSUBO(SDNode *N);
SDValue visitADDE(SDNode *N);
SDValue visitADDCARRY(SDNode *N);
+ SDValue visitADDCARRYLike(SDValue N0, SDValue N1, SDValue CarryIn, SDNode *N);
SDValue visitSUBE(SDNode *N);
SDValue visitSUBCARRY(SDNode *N);
SDValue visitMUL(SDNode *N);
@@ -2142,6 +2143,24 @@
if (isNullConstant(CarryIn))
return DAG.getNode(ISD::UADDO, SDLoc(N), N->getVTList(), N0, N1);
+ if (SDValue Combined = visitADDCARRYLike(N0, N1, CarryIn, N))
+ return Combined;
+
+ if (SDValue Combined = visitADDCARRYLike(N1, N0, CarryIn, N))
+ return Combined;
+
+ return SDValue();
+}
+
+SDValue DAGCombiner::visitADDCARRYLike(SDValue N0, SDValue N1, SDValue CarryIn,
+ SDNode *N) {
+ // Iff the flag result is dead:
+ // (addcarry (add|uaddo X, Y), 0, Carry) -> (addcarry X, Y, Carry)
+ if ((N0.getOpcode() == ISD::ADD || N0.getOpcode() == ISD::UADDO) &&
+ isNullConstant(N1) && !N->hasAnyUseOfValue(1))
+ return DAG.getNode(ISD::ADDCARRY, SDLoc(N), N->getVTList(),
+ N0.getOperand(0), N0.getOperand(1), CarryIn);
+
return SDValue();
}
Index: llvm/trunk/test/CodeGen/X86/addcarry.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/addcarry.ll
+++ llvm/trunk/test/CodeGen/X86/addcarry.ll
@@ -190,9 +190,9 @@
define i64 @shiftadd(i64 %a, i64 %b, i64 %c, i64 %d) {
; CHECK-LABEL: shiftadd:
; CHECK: # BB#0: # %entry
-; CHECK-NEXT: leaq (%rdx,%rcx), %rax
; CHECK-NEXT: addq %rsi, %rdi
-; CHECK-NEXT: adcq $0, %rax
+; CHECK-NEXT: adcq %rcx, %rdx
+; CHECK-NEXT: movq %rdx, %rax
; CHECK-NEXT: retq
entry:
%0 = zext i64 %a to i128
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