[llvm] r304401 - [DAGCombine] (add/uaddo X, Carry) -> (addcarry X, 0, Carry)
Amaury Sechet via llvm-commits
llvm-commits at lists.llvm.org
Thu Jun 1 03:42:39 PDT 2017
Author: deadalnix
Date: Thu Jun 1 05:42:39 2017
New Revision: 304401
URL: http://llvm.org/viewvc/llvm-project?rev=304401&view=rev
Log:
[DAGCombine] (add/uaddo X, Carry) -> (addcarry X, 0, Carry)
Summary:
This enables further transforms.
Depends on D32916
Reviewers: jyknight, nemanjai, mkuper, spatel, RKSimon, zvi, bkramer
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D32925
Modified:
llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
llvm/trunk/test/CodeGen/X86/add-of-carry.ll
llvm/trunk/test/CodeGen/X86/addcarry.ll
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=304401&r1=304400&r2=304401&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Thu Jun 1 05:42:39 2017
@@ -1970,6 +1970,44 @@ SDValue DAGCombiner::visitADD(SDNode *N)
return SDValue();
}
+static SDValue getAsCarry(const TargetLowering &TLI, SDValue V) {
+ bool Masked = false;
+
+ // First, peel away TRUNCATE/ZERO_EXTEND/AND nodes due to legalization.
+ while (true) {
+ if (V.getOpcode() == ISD::TRUNCATE || V.getOpcode() == ISD::ZERO_EXTEND) {
+ V = V.getOperand(0);
+ continue;
+ }
+
+ if (V.getOpcode() == ISD::AND && isOneConstant(V.getOperand(1))) {
+ Masked = true;
+ V = V.getOperand(0);
+ continue;
+ }
+
+ break;
+ }
+
+ // If this is not a carry, return.
+ if (V.getResNo() != 1)
+ return SDValue();
+
+ if (V.getOpcode() != ISD::ADDCARRY && V.getOpcode() != ISD::SUBCARRY &&
+ V.getOpcode() != ISD::UADDO && V.getOpcode() != ISD::USUBO)
+ return SDValue();
+
+ // If the result is masked, then no matter what kind of bool it is we can
+ // return. If it isn't, then we need to make sure the bool type is either 0 or
+ // 1 and not other values.
+ if (Masked ||
+ TLI.getBooleanContents(V.getValueType()) ==
+ TargetLoweringBase::ZeroOrOneBooleanContent)
+ return V;
+
+ return SDValue();
+}
+
SDValue DAGCombiner::visitADDLike(SDValue N0, SDValue N1, SDNode *LocReference) {
EVT VT = N0.getValueType();
SDLoc DL(LocReference);
@@ -2017,6 +2055,12 @@ SDValue DAGCombiner::visitADDLike(SDValu
return DAG.getNode(ISD::ADDCARRY, DL, N1->getVTList(),
N0, N1.getOperand(0), N1.getOperand(2));
+ // (add X, Carry) -> (addcarry X, 0, Carry)
+ if (SDValue Carry = getAsCarry(TLI, N1))
+ return DAG.getNode(ISD::ADDCARRY, DL,
+ DAG.getVTList(VT, Carry.getValueType()), N0,
+ DAG.getConstant(0, DL, VT), Carry);
+
return SDValue();
}
@@ -2100,6 +2144,11 @@ SDValue DAGCombiner::visitUADDOLike(SDVa
N1.getOperand(2));
}
+ // (uaddo X, Carry) -> (addcarry X, 0, Carry)
+ if (SDValue Carry = getAsCarry(TLI, N1))
+ return DAG.getNode(ISD::ADDCARRY, SDLoc(N), N->getVTList(), N0,
+ DAG.getConstant(0, SDLoc(N), N0.getValueType()), Carry);
+
return SDValue();
}
Modified: llvm/trunk/test/CodeGen/X86/add-of-carry.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/add-of-carry.ll?rev=304401&r1=304400&r2=304401&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/add-of-carry.ll (original)
+++ llvm/trunk/test/CodeGen/X86/add-of-carry.ll Thu Jun 1 05:42:39 2017
@@ -9,9 +9,11 @@
define i32 @test1(i32 %sum, i32 %x) nounwind readnone ssp {
; CHECK-LABEL: test1:
; CHECK: # BB#0:
+; CHECK-NEXT: movl {{[0-9]+}}(%esp), %ecx
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %eax
-; CHECK-NEXT: addl {{[0-9]+}}(%esp), %eax
-; CHECK-NEXT: adcl $0, %eax
+; CHECK-NEXT: movl %eax, %edx
+; CHECK-NEXT: addl %ecx, %edx
+; CHECK-NEXT: adcl %ecx, %eax
; CHECK-NEXT: retl
%add4 = add i32 %x, %sum
%cmp = icmp ult i32 %add4, %x
Modified: llvm/trunk/test/CodeGen/X86/addcarry.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/addcarry.ll?rev=304401&r1=304400&r2=304401&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/addcarry.ll (original)
+++ llvm/trunk/test/CodeGen/X86/addcarry.ll Thu Jun 1 05:42:39 2017
@@ -190,9 +190,9 @@ entry:
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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