make m_ConstantInt(int64_t) safely match ConstantInt's that are larger than i64.

This fixes an instcombine crash on PR3235.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61775 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 10 insertions, 1 deletions

diff --git a/include/llvm/Support/PatternMatch.h b/include/llvm/Support/PatternMatch.h
index 035dcf5..55b4b6a 100644
--- a/include/llvm/Support/PatternMatch.h
+++ b/include/llvm/Support/PatternMatch.h
@@ -57,7 +57,16 @@ struct constantint_ty {
 
   template<typename ITy>
   bool match(ITy *V) {
-    return isa<ConstantInt>(V) && cast<ConstantInt>(V)->getSExtValue() == Val;
+    if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
+      const APInt &CIV = CI->getValue();
+      if (Val > 0)
+        return CIV == Val;
+      // If Val is negative, and CI is shorter than it, truncate to the right
+      // number of bits.  If it is larger, then we have to sign extend.  Just
+      // compare their negated values.
+      return -CIV == -Val;
+    }
+    return false;
   }
 };