llvm-reduce: Do not crash on operands with vector of pointer type

[MatzeB]

Summary

Avoid crash in reduceOperandsOneDeltaPass function for operands with vector of pointer type.

While on it add a reduce-operands-ptr.ll test in the spirit of the existing reduce-operands-int.ll/reduce-operands-fp.ll tests.

llvm/test/tools/llvm-reduce/reduce-operands-ptr.ll

+; Test that llvm-reduce can reduce pointer operands
+; RUN: llvm-reduce --abort-on-invalid-reduction --delta-passes=operands-one --test FileCheck --test-arg --check-prefixes=CHECK-INTERESTINGNESS --test-arg %s --test-arg --input-file %s -o %t
+; RUN: FileCheck --check-prefixes=CHECK,ONE %s < %t
+
+; RUN: llvm-reduce --abort-on-invalid-reduction --delta-passes=operands-zero --test FileCheck --test-arg --check-prefixes=CHECK-INTERESTINGNESS --test-arg %s --test-arg --input-file %s -o %t
+; RUN: FileCheck --check-prefixes=CHECK,ZERO %s < %t
+
+; RUN: llvm-reduce --abort-on-invalid-reduction --test FileCheck --test-arg --check-prefixes=CHECK-INTERESTINGNESS --test-arg %s --test-arg --input-file %s -o %t
+; RUN: FileCheck --check-prefixes=CHECK,ZERO %s < %t
+
+; CHECK-LABEL: define void @foo(
+
+; ONE: load i32, ptr %a0
+; ONE: load i32, ptr @g
+; ONE: extractelement <4 x ptr> <ptr @g, ptr null, ptr @g, ptr @g>, i32 11
+
+; ZERO: load i32, ptr null
+; ZERO: load i32, ptr null
+; ZERO: extractelement <4 x ptr> zeroinitializer, i32 11
+
+@g = global i32 0
+
+define void @foo(ptr %a0) {
+  ; CHECK-INTERESTINGNESS: load i32
+  %v0 = load i32, ptr %a0
+  ; CHECK-INTERESTINGNESS: load i32
+  %v1 = load i32, ptr @g
+
+  ; CHECK-INTERESTINGNESS: extractelement{{.*}}i32 11
+  %v2 = extractelement <4 x ptr> <ptr @g, ptr null, ptr @g, ptr @g>, i32 11
+
+  ret void
+}

llvm/tools/llvm-reduce/deltas/ReduceOperands.cpp

auto ReduceValue = [](Use &Op) -> Value * {
 
     if (Ty->isFloatingPointTy())
       return isZeroOrOneFP(Op) ? nullptr : ConstantFP::get(Ty, 1.0);
 
     if (VectorType *VT = dyn_cast<VectorType>(Ty)) {
       if (isOne(Op) || isZero(Op) || isZeroOrOneFP(Op))
         return nullptr;
 
-      if (auto *IntTy = dyn_cast<IntegerType>(VT->getElementType()))
-        return ConstantVector::getSplat(VT->getElementCount(),
-                                        ConstantInt::get(IntTy, 1));
-
-      return ConstantVector::getSplat(
-          VT->getElementCount(), ConstantFP::get(VT->getElementType(), 1.0));
+      Type *ElementType = VT->getElementType();
+      Constant *C;
+      if (ElementType->isFloatingPointTy()) {
+        C = ConstantFP::get(ElementType, 1.0);
+      } else if (IntegerType *IntTy = dyn_cast<IntegerType>(ElementType)) {
+        C = ConstantInt::get(IntTy, 1);
+      } else {
+        return nullptr;
+      }
+      return ConstantVector::getSplat(VT->getElementCount(), C);
     }
 
     return nullptr;
   };
   runDeltaPass(Test, [ReduceValue](Oracle &O, Module &Program) {
     extractOperandsFromModule(O, Program, ReduceValue);
   });
 }