[LoongArch] Improve pattern matching for AddLike predicate

[heiher]

This commit updates the pattern matching logic for the AddLike predicate in LoongArchInstrInfo.td to use the isBaseWithConstantOffset function provided by CurDAG. This optimization aims to improve the efficiency of pattern matching by identifying cases where the operation can be represented as a base address plus a constant offset, which can lead to more efficient code generation.

[llvmbot]

@llvm/pr-subscribers-llvm-selectiondag

@llvm/pr-subscribers-backend-loongarch

Author: hev (heiher)

Changes

SelectionDAGISel::isOrEquivalentToAdd can only test operands that are directly based on the stack frame. The improvement in this commit is to add a call to SelectionDAG::haveNoCommonBitsSet for testing, which helps optimize the code generation for load (or base, imm).

---

Full diff: https://github.com/llvm/llvm-project/pull/82767.diff

2 Files Affected:

• (modified) llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp (+1-1)
• (modified) llvm/test/CodeGen/LoongArch/intrinsic-memcpy.ll (+1-2)

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 9b5ab4267b80e9..0cf9a02af35c49 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -4214,7 +4214,7 @@ bool SelectionDAGISel::isOrEquivalentToAdd(const SDNode *N) const {
     // the alignment, then this or is really an add.
     return (Off >= 0) && (((A.value() - 1) & Off) == unsigned(Off));
   }
-  return false;
+  return CurDAG->haveNoCommonBitsSet(N->getOperand(0), N->getOperand(1));
 }
 
 void SelectionDAGISel::CannotYetSelect(SDNode *N) {
diff --git a/llvm/test/CodeGen/LoongArch/intrinsic-memcpy.ll b/llvm/test/CodeGen/LoongArch/intrinsic-memcpy.ll
index 09453004dcef74..ff845cb1f3dbd9 100644
--- a/llvm/test/CodeGen/LoongArch/intrinsic-memcpy.ll
+++ b/llvm/test/CodeGen/LoongArch/intrinsic-memcpy.ll
@@ -22,8 +22,7 @@ define void @box(ptr noalias nocapture noundef writeonly sret(%Box) align 16 der
 ; CHECK-NEXT:    st.d $a1, $a0, 24
 ; CHECK-NEXT:    ld.d $a1, $a3, 16
 ; CHECK-NEXT:    st.d $a1, $a0, 16
-; CHECK-NEXT:    ori $a1, $a3, 8
-; CHECK-NEXT:    ld.d $a1, $a1, 0
+; CHECK-NEXT:    ld.d $a1, $a3, 8
 ; CHECK-NEXT:    st.d $a1, $a0, 8
 ; CHECK-NEXT:    addi.d $sp, $sp, 96
 ; CHECK-NEXT:    ret

[topperc]

LGTM