[llvm] r301919 - [DAGCombine] (add X, (addcarry Y, 0, Carry)) -> (addcarry X, Y, Carry)

[Amaury Sechet via llvm-commits]

Author: deadalnix
Date: Tue May  2 08:34:25 2017
New Revision: 301919

URL: http://llvm.org/viewvc/llvm-project?rev=301919&view=rev
Log:
[DAGCombine] (add X, (addcarry Y, 0, Carry)) -> (addcarry X, Y, Carry)

Summary: Common pattern when legalizing large integers operations. Similar to D32687, when the carry isn't used.

Reviewers: jyknight, nemanjai, mkuper, spatel, RKSimon, zvi, bkramer

Differential Revision: https://reviews.llvm.org/D32738

Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
    llvm/trunk/test/CodeGen/X86/adde-carry.ll

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=301919&r1=301918&r2=301919&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Tue May  2 08:34:25 2017
@@ -2015,6 +2015,11 @@ SDValue DAGCombiner::visitADDLike(SDValu
     }
   }
 
+  // (add X, (addcarry Y, 0, Carry)) -> (addcarry X, Y, Carry)
+  if (N1.getOpcode() == ISD::ADDCARRY && isNullConstant(N1.getOperand(1)))
+    return DAG.getNode(ISD::ADDCARRY, DL, N1->getVTList(),
+                       N0, N1.getOperand(0), N1.getOperand(2));
+
   return SDValue();
 }
 

Modified: llvm/trunk/test/CodeGen/X86/adde-carry.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/adde-carry.ll?rev=301919&r1=301918&r2=301919&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/adde-carry.ll (original)
+++ llvm/trunk/test/CodeGen/X86/adde-carry.ll Tue May  2 08:34:25 2017
@@ -47,7 +47,7 @@ define void @c(i16* nocapture %r, i64 %a
 ; CHECK-LABEL: c:
 ; CHECK:       # BB#0: # %entry
 ; CHECK-NEXT:    addq %rdx, %rsi
-; CHECK-NEXT:    adcl $0, %ecx
+; CHECK-NEXT:    adcw $0, %cx
 ; CHECK-NEXT:    movw %cx, (%rdi)
 ; CHECK-NEXT:    retq
 entry:
@@ -66,7 +66,7 @@ define void @d(i8* nocapture %r, i64 %a,
 ; CHECK-LABEL: d:
 ; CHECK:       # BB#0: # %entry
 ; CHECK-NEXT:    addq %rdx, %rsi
-; CHECK-NEXT:    adcl $0, %ecx
+; CHECK-NEXT:    adcb $0, %cl
 ; CHECK-NEXT:    movb %cl, (%rdi)
 ; CHECK-NEXT:    retq
 entry:
@@ -90,17 +90,16 @@ define %scalar @pr31719(%scalar* nocaptu
 ; CHECK-NEXT:    sbbq %r10, %r10
 ; CHECK-NEXT:    andl $1, %r10d
 ; CHECK-NEXT:    addq 8(%rsi), %rcx
-; CHECK-NEXT:    sbbq %r11, %r11
-; CHECK-NEXT:    andl $1, %r11d
-; CHECK-NEXT:    addq %r10, %rcx
-; CHECK-NEXT:    adcq $0, %r11
-; CHECK-NEXT:    addq 16(%rsi), %r8
 ; CHECK-NEXT:    sbbq %rax, %rax
 ; CHECK-NEXT:    andl $1, %eax
-; CHECK-NEXT:    addq %r11, %r8
+; CHECK-NEXT:    addq %r10, %rcx
 ; CHECK-NEXT:    adcq $0, %rax
+; CHECK-NEXT:    addq 16(%rsi), %r8
+; CHECK-NEXT:    sbbq %r10, %r10
+; CHECK-NEXT:    andl $1, %r10d
 ; CHECK-NEXT:    addq 24(%rsi), %r9
-; CHECK-NEXT:    addq %rax, %r9
+; CHECK-NEXT:    addq %rax, %r8
+; CHECK-NEXT:    adcq %r10, %r9
 ; CHECK-NEXT:    movq %rdx, (%rdi)
 ; CHECK-NEXT:    movq %rcx, 8(%rdi)
 ; CHECK-NEXT:    movq %r8, 16(%rdi)
@@ -163,8 +162,7 @@ define void @muladd(%accumulator* nocapt
 ; CHECK-NEXT:    movq %rax, (%rdi)
 ; CHECK-NEXT:    addq 8(%rdi), %rdx
 ; CHECK-NEXT:    movq %rdx, 8(%rdi)
-; CHECK-NEXT:    sbbl %eax, %eax
-; CHECK-NEXT:    subl %eax, 16(%rdi)
+; CHECK-NEXT:    adcl $0, 16(%rdi)
 ; CHECK-NEXT:    retq
 entry:
   %0 = zext i64 %arg.a to i128