[llvm] [VPlan] Introduce m_Cmp; match more compares (PR #154771)

[Luke Lau via llvm-commits]

================
@@ -1106,18 +1106,16 @@ static void simplifyRecipe(VPRecipeBase &R, VPTypeAnalysis &TypeInfo) {
       return Def->replaceAllUsesWith(A);
 
     // Try to fold Not into compares by adjusting the predicate in-place.
-    if (isa<VPWidenRecipe>(A) && A->getNumUsers() == 1) {
-      auto *WideCmp = cast<VPWidenRecipe>(A);
-      if (WideCmp->getOpcode() == Instruction::ICmp ||
-          WideCmp->getOpcode() == Instruction::FCmp) {
-        WideCmp->setPredicate(
-            CmpInst::getInversePredicate(WideCmp->getPredicate()));
-        Def->replaceAllUsesWith(WideCmp);
-        // If WideCmp doesn't have a debug location, use the one from the
-        // negation, to preserve the location.
-        if (!WideCmp->getDebugLoc() && R.getDebugLoc())
-          WideCmp->setDebugLoc(R.getDebugLoc());
-      }
+    CmpPredicate Pred;
+    if (match(A, m_Cmp(Pred, m_VPValue(), m_VPValue())) &&
+        A->getNumUsers() == 1) {
+      auto *Cmp = cast<VPRecipeWithIRFlags>(A);
+      Cmp->setPredicate(CmpInst::getInversePredicate(Pred));
+      Def->replaceAllUsesWith(Cmp);
+      // If WideCmp doesn't have a debug location, use the one from the
----------------
lukel97 wrote:

```suggestion
      // If Cmp doesn't have a debug location, use the one from the
```

https://github.com/llvm/llvm-project/pull/154771