[IndVars] Add check of loop invariant for indirect use

We usually only check direct use instruction of IV, while the
bitcast of 'ptrtoint ptr to i64' doesn't affect the result, so go
a step further.
Fix #59633.

Reviewed By: markoshorro
Differential Revision: https://reviews.llvm.org/D151877

Author: vfdff

llvm/lib/Transforms/Utils/SimplifyIndVar.cpp

@@ -908,6 +908,14 @@ void SimplifyIndvar::simplifyUsers(PHINode *CurrIV, IVVisitor *V) {
     if (replaceIVUserWithLoopInvariant(UseInst))
       continue;
 
+    // Go further for the bitcast ''prtoint ptr to i64'
+    if (isa<PtrToIntInst>(UseInst))
+      for (Use &U : UseInst->uses()) {
+        Instruction *User = cast<Instruction>(U.getUser());
+        if (replaceIVUserWithLoopInvariant(User))
+          break; // done replacing
+      }
+
     Instruction *IVOperand = UseOper.second;
     for (unsigned N = 0; IVOperand; ++N) {
       assert(N <= Simplified.size() && "runaway iteration");

llvm/test/Transforms/IndVarSimplify/pr59633.ll

@@ -0,0 +1,29 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -passes=indvars -S | FileCheck %s
+
+declare void @foo(i64 noundef)
+
+; Function Attrs: mustprogress noreturn uwtable
+define void @pr59633(ptr noundef %ptr) {
+; CHECK-LABEL: @pr59633(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[PTR1:%.*]] = ptrtoint ptr [[PTR:%.*]] to i64
+; CHECK-NEXT:    [[TMP0:%.*]] = trunc i64 [[PTR1]] to i4
+; CHECK-NEXT:    [[TMP1:%.*]] = zext i4 [[TMP0]] to i64
+; CHECK-NEXT:    br label [[WHILE_BODY:%.*]]
+; CHECK:       while.body:
+; CHECK-NEXT:    tail call void @foo(i64 noundef [[TMP1]])
+; CHECK-NEXT:    br label [[WHILE_BODY]]
+;
+entry:
+  br label %while.body
+
+while.body:                                       ; preds = %entry, %while.body
+  %ptr.addr.0 = phi ptr [ %ptr, %entry ], [ %add.ptr, %while.body ]
+  %0 = ptrtoint ptr %ptr.addr.0 to i64
+  %and = and i64 %0, 15                           ; loop invariant
+  tail call void @foo(i64 noundef %and)
+  %add.ptr = getelementptr inbounds i8, ptr %ptr.addr.0, i64 16
+  br label %while.body
+}
+