Index: llvm/trunk/include/llvm/IR/Operator.h
===================================================================
--- llvm/trunk/include/llvm/IR/Operator.h
+++ llvm/trunk/include/llvm/IR/Operator.h
@@ -328,8 +328,15 @@
     return I->getType()->isFPOrFPVectorTy() ||
       I->getOpcode() == Instruction::FCmp;
   }
+
+  static inline bool classof(const ConstantExpr *CE) {
+    return CE->getType()->isFPOrFPVectorTy() ||
+           CE->getOpcode() == Instruction::FCmp;
+  }
+
   static inline bool classof(const Value *V) {
-    return isa<Instruction>(V) && classof(cast<Instruction>(V));
+    return (isa<Instruction>(V) && classof(cast<Instruction>(V))) ||
+           (isa<ConstantExpr>(V) && classof(cast<ConstantExpr>(V)));
   }
 };
 
Index: llvm/trunk/test/Transforms/InstCombine/pr33453.ll
===================================================================
--- llvm/trunk/test/Transforms/InstCombine/pr33453.ll
+++ llvm/trunk/test/Transforms/InstCombine/pr33453.ll
@@ -0,0 +1,15 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -instcombine -S %s | FileCheck %s
+
+@g1 = external global i16
+@g2 = external global i16
+
+define float @patatino() {
+; CHECK-LABEL: @patatino(
+; CHECK-NEXT:    ret float fmul (float uitofp (i1 icmp eq (i16* getelementptr inbounds (i16, i16* @g2, i64 1), i16* @g1) to float), float uitofp (i1 icmp eq (i16* getelementptr inbounds (i16, i16* @g2, i64 1), i16* @g1) to float))
+;
+  %call = call float @fabsf(float fmul (float uitofp (i1 icmp eq (i16* getelementptr inbounds (i16, i16* @g2, i64 1), i16* @g1) to float), float uitofp (i1 icmp eq (i16* getelementptr inbounds (i16, i16* @g2, i64 1), i16* @g1) to float)))
+  ret float %call
+}
+
+declare float @fabsf(float)