[llvm] [InstCombine] Remove one-use restriction on icmp of gep fold (PR #76730)

[Yingwei Zheng via llvm-commits]

================
@@ -813,14 +813,29 @@ Instruction *InstCombinerImpl::foldGEPICmp(GEPOperator *GEPLHS, Value *RHS,
       }
     }
 
-    // Only lower this if the icmp is the only user of the GEP or if we expect
-    // the result to fold to a constant!
-    if ((GEPsInBounds || CmpInst::isEquality(Cond)) &&
-        (GEPLHS->hasAllConstantIndices() || GEPLHS->hasOneUse()) &&
-        (GEPRHS->hasAllConstantIndices() || GEPRHS->hasOneUse())) {
+    if (GEPsInBounds || CmpInst::isEquality(Cond)) {
+      auto EmitGEPOffsetAndRewrite = [&](GEPOperator *GEP) {
+        auto *Inst = dyn_cast<Instruction>(GEP);
----------------
dtcxzyw wrote:

IIRC we have removed constant expr support for `getelementptr`. I cannot find the pattern `(getelementptr` in the LLVM regression tests and my benchmarks.

If not, should we restore the insert point after offset expansion?


https://github.com/llvm/llvm-project/pull/76730