[llvm] afdaa86 - [DAGCombine] Extend combineCarryDiamond()

[Paweł Bylica via llvm-commits]

Author: Pawe Bylica
Date: 2022-02-23T21:37:49+01:00
New Revision: afdaa86b771f9fa7bcf3ac273ae6f9637943c0d1

URL: https://github.com/llvm/llvm-project/commit/afdaa86b771f9fa7bcf3ac273ae6f9637943c0d1
DIFF: https://github.com/llvm/llvm-project/commit/afdaa86b771f9fa7bcf3ac273ae6f9637943c0d1.diff

LOG: [DAGCombine] Extend combineCarryDiamond()

In combineCarryDiamond() use getAsCarry() to find more candidates for being a carry flag.

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D118362

Added: 
    

Modified: 
    llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
    llvm/test/CodeGen/X86/addcarry.ll

Removed: 
    


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diff  --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 6c5286277ba9d..4ed38c3ea243c 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -3137,9 +3137,14 @@ static SDValue combineADDCARRYDiamond(DAGCombiner &Combiner, SelectionDAG &DAG,
 // Our goal is to identify A, B, and CarryIn and produce ADDCARRY/SUBCARRY with
 // a single path for carry/borrow out propagation:
 static SDValue combineCarryDiamond(SelectionDAG &DAG, const TargetLowering &TLI,
-                                   SDValue Carry0, SDValue Carry1, SDNode *N) {
-  if (Carry0.getResNo() != 1 || Carry1.getResNo() != 1)
+                                   SDValue N0, SDValue N1, SDNode *N) {
+  SDValue Carry0 = getAsCarry(TLI, N0);
+  if (!Carry0)
     return SDValue();
+  SDValue Carry1 = getAsCarry(TLI, N1);
+  if (!Carry1)
+    return SDValue();
+
   unsigned Opcode = Carry0.getOpcode();
   if (Opcode != Carry1.getOpcode())
     return SDValue();

diff  --git a/llvm/test/CodeGen/X86/addcarry.ll b/llvm/test/CodeGen/X86/addcarry.ll
index 02c2110b37b9c..3d996619c94ba 100644
--- a/llvm/test/CodeGen/X86/addcarry.ll
+++ b/llvm/test/CodeGen/X86/addcarry.ll
@@ -451,12 +451,9 @@ define { i64, i64, i1 } @addcarry_hidden_2x64(i64 %x0, i64 %x1, i64 %y0, i64 %y1
 ; CHECK-LABEL: addcarry_hidden_2x64:
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    movq %rdi, %rax
-; CHECK-NEXT:    addq %rcx, %rsi
-; CHECK-NEXT:    setb %dil
 ; CHECK-NEXT:    addq %rdx, %rax
-; CHECK-NEXT:    adcq $0, %rsi
+; CHECK-NEXT:    adcq %rcx, %rsi
 ; CHECK-NEXT:    setb %cl
-; CHECK-NEXT:    orb %dil, %cl
 ; CHECK-NEXT:    movq %rsi, %rdx
 ; CHECK-NEXT:    retq
   %t0 = call { i64, i1 } @llvm.uadd.with.overflow.i64(i64 %x0, i64 %y0)