[SimplifyCFG] teach simplifycfg not to introduce ptrtoint for NI pointers

SimplifyCFG expects to be able to cast both sides to an int, if either side can be case to an int, but this is not desirable or legal, in general, per D104547.

Spotted in JuliaLang/julia#45702

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D128670

Author: vtjnash

llvm/lib/Transforms/Utils/SimplifyCFG.cpp

@@ -473,7 +473,8 @@ static bool dominatesMergePoint(Value *V, BasicBlock *BB,
 static ConstantInt *GetConstantInt(Value *V, const DataLayout &DL) {
   // Normal constant int.
   ConstantInt *CI = dyn_cast<ConstantInt>(V);
-  if (CI || !isa<Constant>(V) || !V->getType()->isPointerTy())
+  if (CI || !isa<Constant>(V) || !V->getType()->isPointerTy() ||
+      DL.isNonIntegralPointerType(V->getType()))
     return CI;
 
   // This is some kind of pointer constant. Turn it into a pointer-sized

llvm/test/Transforms/SimplifyCFG/nonintegral.ll

@@ -0,0 +1,28 @@
+; RUN: opt -passes=simplifycfg -S < %s | FileCheck %s
+
+target datalayout = "ni:1"
+
+define void @test_01(i64 addrspace(1)* align 8 %ptr) {
+; CHECK-LABEL: @test_01(
+; CHECK-NOT:   ptrtoint
+; CHECK-NEXT:  icmp eq i64 addrspace(1)* %ptr, null
+; CHECK-NOT:   ptrtoint
+  %cond1 = icmp eq i64 addrspace(1)* %ptr, null
+  %cond2 = icmp eq i64 addrspace(1)* %ptr, null
+  br i1 %cond1, label %true1, label %false1
+
+true1:
+  br i1 %cond2, label %true2, label %false2
+
+false1:
+  store i64 1, i64 addrspace(1)* %ptr, align 8
+  br label %true1
+
+true2:
+  store i64 2, i64 addrspace(1)* %ptr, align 8
+  ret void
+
+false2:
+  store i64 3, i64 addrspace(1)* %ptr, align 8
+  ret void
+}