[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 https://github.com/llvm/llvm-project/issues/59633.

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

1 files changed, 8 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
index 62821f1..a28916b 100644
--- a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
+++ b/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");