[PATCH] D13029: [PatternMatch] Switch to using ValueTracking::matchSelectPattern for min/max matching

[David Majnemer via llvm-commits]

majnemer added inline comments.

================
Comment at: include/llvm/IR/PatternMatch.h:959-962
@@ -957,5 +958,6 @@
   template <typename OpTy> bool match(OpTy *V) {
-    // Look for "(x pred y) ? x : y" or "(x pred y) ? y : x".
-    auto *SI = dyn_cast<SelectInst>(V);
-    if (!SI)
+    // matchSelectPattern can get expensive, so do some early bailout checks
+    // first.
+    if (!isa<SelectInst>(V) ||
+        !isa<CmpInst>(cast<SelectInst>(V)->getCondition()))
       return false;
----------------
Unless I'm mistaken, isn't this what `llvm::matchSelectPattern` already does?  I'd be surprised if the extra call frame matters here.


Repository:
  rL LLVM

http://reviews.llvm.org/D13029