[VPlanPatternMatch] Introduce m_ConstantInt

[artagnon]

No description provided.

[llvmbot]

@llvm/pr-subscribers-vectorizers

@llvm/pr-subscribers-llvm-transforms

Author: Ramkumar Ramachandra (artagnon)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/159558.diff

2 Files Affected:

• (modified) llvm/lib/Transforms/Vectorize/VPlanPatternMatch.h (+26)
• (modified) llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp (+5-4)

diff --git a/llvm/lib/Transforms/Vectorize/VPlanPatternMatch.h b/llvm/lib/Transforms/Vectorize/VPlanPatternMatch.h
index 8f9ce7a74b58b..7da75473ba00e 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanPatternMatch.h
+++ b/llvm/lib/Transforms/Vectorize/VPlanPatternMatch.h
@@ -176,6 +176,32 @@ inline int_pred_ty<is_zero_int> m_ZeroInt() {
 /// For vectors, this includes constants with undefined elements.
 inline int_pred_ty<is_one> m_One() { return int_pred_ty<is_one>(); }
 
+struct apint_match {
+  const APInt *&Res;
+
+  apint_match(const APInt *&Res) : Res(Res) {}
+
+  bool match(VPValue *VPV) const {
+    if (!VPV->isLiveIn())
+      return false;
+    Value *V = VPV->getLiveInIRValue();
+    if (!V)
+      return false;
+    const auto *CI = dyn_cast<ConstantInt>(V);
+    if (!CI && V->getType()->isVectorTy())
+      if (const auto *C = dyn_cast<Constant>(V))
+        CI = dyn_cast_or_null<ConstantInt>(
+            C->getSplatValue(/*AllowPoison=*/false));
+    if (!CI)
+      return false;
+    Res = &CI->getValue();
+    return true;
+  }
+};
+
+/// Match an APInt, capturing it if we match.
+inline apint_match m_APInt(const APInt *&C) { return C; }
+
 /// Matching combinators
 template <typename LTy, typename RTy> struct match_combine_or {
   LTy L;
diff --git a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
index 9996b0167edcb..c71655f08bf49 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
@@ -1592,11 +1592,12 @@ static bool tryToReplaceALMWithWideALM(VPlan &Plan, ElementCount VF,
           m_ActiveLaneMask(m_VPValue(Index), m_VPValue(), m_VPValue()));
     assert(Index && "Expected index from ActiveLaneMask instruction");
 
-    auto *II = dyn_cast<VPInstruction>(Index);
-    if (II && II->getOpcode() == VPInstruction::CanonicalIVIncrementForPart) {
-      auto Part = cast<ConstantInt>(II->getOperand(1)->getLiveInIRValue());
+    const APInt *Part;
+    if (match(Index,
+              m_VPInstruction<VPInstruction::CanonicalIVIncrementForPart>(
+                  m_VPValue(), m_APInt(Part))))
       Phis[Part->getZExtValue()] = Phi;
-    } else
+    else
       // Anything other than a CanonicalIVIncrementForPart is part 0
       Phis[0] = Phi;
   }

[lukel97]

Not sure if we will ever need to match and capture an APInt in VPlan but I guess this mirrors PatternMatch.h.

[fhahn]

Seems like it would be simpler to first only have a m_ConstantInt instead of adding the extra indirection

[fhahn]

LGTM, thanks