[llvm] Fix assertion error in AArch64 (PR #154124)

[via llvm-commits]

https://github.com/AZero13 created https://github.com/llvm/llvm-project/pull/154124

None

>From 7c8a2d71e18d9949d2f5288e50794caac0e1375b Mon Sep 17 00:00:00 2001
From: AZero13 <gfunni234 at gmail.com>
Date: Mon, 18 Aug 2025 10:32:11 -0400
Subject: [PATCH] Fix assertion error.

---
 .../Target/AArch64/GISel/AArch64PostLegalizerLowering.cpp   | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerLowering.cpp b/llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerLowering.cpp
index 2abe0dd0bbdc2..6025f1c9f5f4e 100644
--- a/llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerLowering.cpp
+++ b/llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerLowering.cpp
@@ -639,8 +639,10 @@ tryAdjustICmpImmAndPred(Register RHS, CmpInst::Predicate P,
     // x ule c => x ult c + 1
     // x ugt c => s uge c + 1
     //
-    assert(C != (Size == 32 ? UINT32_MAX : UINT64_MAX) &&
-           "C should not be -1 here!");
+    // When c is not the largest possible unsigned integer.
+    if ((Size == 32 && static_cast<uint32_t>(C) == UINT32_MAX) ||
+        (Size == 64 && C == UINT64_MAX))
+      return std::nullopt;
     P = (P == CmpInst::ICMP_ULE) ? CmpInst::ICMP_ULT : CmpInst::ICMP_UGE;
     C += 1;
     break;