[llvm] c8cc790 - [SelectionDAG] Replace some basic patterns in visitADDLike with SDPatternMatch (#84759)

[via llvm-commits]

Author: XChy
Date: 2024-03-13T00:33:50+08:00
New Revision: c8cc7903b373589cc85271987980ae277145df7c

URL: https://github.com/llvm/llvm-project/commit/c8cc7903b373589cc85271987980ae277145df7c
DIFF: https://github.com/llvm/llvm-project/commit/c8cc7903b373589cc85271987980ae277145df7c.diff

LOG: [SelectionDAG] Replace some basic patterns in visitADDLike with SDPatternMatch (#84759)

Resolves #84745.

Based on SDPatternMatch introduced by #78654, this patch replaces some
of basic patterns in `visitADDLike` with corresponding patterns in
SDPatternMatch.

This patch only replaces original folds, instead of introducing new ones.

Added: 
    

Modified: 
    llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

Removed: 
    


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diff  --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 5476ef87971436..735cec8ecc0627 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -38,6 +38,7 @@
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineMemOperand.h"
 #include "llvm/CodeGen/RuntimeLibcalls.h"
+#include "llvm/CodeGen/SDPatternMatch.h"
 #include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/CodeGen/SelectionDAGAddressAnalysis.h"
 #include "llvm/CodeGen/SelectionDAGNodes.h"
@@ -79,6 +80,7 @@
 #include "MatchContext.h"
 
 using namespace llvm;
+using namespace llvm::SDPatternMatch;
 
 #define DEBUG_TYPE "dagcombine"
 
@@ -2697,52 +2699,45 @@ SDValue DAGCombiner::visitADDLike(SDNode *N) {
             reassociateReduction(ISD::VECREDUCE_ADD, ISD::ADD, DL, VT, N0, N1))
       return SD;
   }
+
+  SDValue A, B, C;
+
   // fold ((0-A) + B) -> B-A
-  if (N0.getOpcode() == ISD::SUB && isNullOrNullSplat(N0.getOperand(0)))
-    return DAG.getNode(ISD::SUB, DL, VT, N1, N0.getOperand(1));
+  if (sd_match(N0, m_Sub(m_Zero(), m_Value(A))))
+    return DAG.getNode(ISD::SUB, DL, VT, N1, A);
 
   // fold (A + (0-B)) -> A-B
-  if (N1.getOpcode() == ISD::SUB && isNullOrNullSplat(N1.getOperand(0)))
-    return DAG.getNode(ISD::SUB, DL, VT, N0, N1.getOperand(1));
+  if (sd_match(N1, m_Sub(m_Zero(), m_Value(B))))
+    return DAG.getNode(ISD::SUB, DL, VT, N0, B);
 
   // fold (A+(B-A)) -> B
-  if (N1.getOpcode() == ISD::SUB && N0 == N1.getOperand(1))
-    return N1.getOperand(0);
+  if (sd_match(N1, m_Sub(m_Value(B), m_Specific(N0))))
+    return B;
 
   // fold ((B-A)+A) -> B
-  if (N0.getOpcode() == ISD::SUB && N1 == N0.getOperand(1))
-    return N0.getOperand(0);
+  if (sd_match(N0, m_Sub(m_Value(B), m_Specific(N1))))
+    return B;
 
   // fold ((A-B)+(C-A)) -> (C-B)
-  if (N0.getOpcode() == ISD::SUB && N1.getOpcode() == ISD::SUB &&
-      N0.getOperand(0) == N1.getOperand(1))
-    return DAG.getNode(ISD::SUB, DL, VT, N1.getOperand(0),
-                       N0.getOperand(1));
+  if (sd_match(N0, m_Sub(m_Value(A), m_Value(B))) &&
+      sd_match(N1, m_Sub(m_Value(C), m_Specific(A))))
+    return DAG.getNode(ISD::SUB, DL, VT, C, B);
 
   // fold ((A-B)+(B-C)) -> (A-C)
-  if (N0.getOpcode() == ISD::SUB && N1.getOpcode() == ISD::SUB &&
-      N0.getOperand(1) == N1.getOperand(0))
-    return DAG.getNode(ISD::SUB, DL, VT, N0.getOperand(0),
-                       N1.getOperand(1));
+  if (sd_match(N0, m_Sub(m_Value(A), m_Value(B))) &&
+      sd_match(N1, m_Sub(m_Specific(B), m_Value(C))))
+    return DAG.getNode(ISD::SUB, DL, VT, A, C);
 
   // fold (A+(B-(A+C))) to (B-C)
-  if (N1.getOpcode() == ISD::SUB && N1.getOperand(1).getOpcode() == ISD::ADD &&
-      N0 == N1.getOperand(1).getOperand(0))
-    return DAG.getNode(ISD::SUB, DL, VT, N1.getOperand(0),
-                       N1.getOperand(1).getOperand(1));
-
   // fold (A+(B-(C+A))) to (B-C)
-  if (N1.getOpcode() == ISD::SUB && N1.getOperand(1).getOpcode() == ISD::ADD &&
-      N0 == N1.getOperand(1).getOperand(1))
-    return DAG.getNode(ISD::SUB, DL, VT, N1.getOperand(0),
-                       N1.getOperand(1).getOperand(0));
+  if (sd_match(N1, m_Sub(m_Value(B), m_Add(m_Specific(N0), m_Value(C)))))
+    return DAG.getNode(ISD::SUB, DL, VT, B, C);
 
   // fold (A+((B-A)+or-C)) to (B+or-C)
-  if ((N1.getOpcode() == ISD::SUB || N1.getOpcode() == ISD::ADD) &&
-      N1.getOperand(0).getOpcode() == ISD::SUB &&
-      N0 == N1.getOperand(0).getOperand(1))
-    return DAG.getNode(N1.getOpcode(), DL, VT, N1.getOperand(0).getOperand(0),
-                       N1.getOperand(1));
+  if (sd_match(N1,
+               m_AnyOf(m_Add(m_Sub(m_Value(B), m_Specific(N0)), m_Value(C)),
+                       m_Sub(m_Sub(m_Value(B), m_Specific(N0)), m_Value(C)))))
+    return DAG.getNode(N1.getOpcode(), DL, VT, B, C);
 
   // fold (A-B)+(C-D) to (A+C)-(B+D) when A or C is constant
   if (N0.getOpcode() == ISD::SUB && N1.getOpcode() == ISD::SUB &&