From a6f797c2fe10880819f6fe8594030415d6b73509 Mon Sep 17 00:00:00 2001
From: Billy Moses <wmoses@google.com>
Date: Sun, 12 Jul 2026 17:34:08 -0500
Subject: [PATCH] GC loaded cache fix

---
 .../JuliaCallingConvention/gcloaded_cache.ll  | 45 +++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 enzyme/test/Enzyme/JuliaCallingConvention/gcloaded_cache.ll

diff --git a/enzyme/test/Enzyme/JuliaCallingConvention/gcloaded_cache.ll b/enzyme/test/Enzyme/JuliaCallingConvention/gcloaded_cache.ll
new file mode 100644
index 00000000000..64c95efa22b
--- /dev/null
+++ b/enzyme/test/Enzyme/JuliaCallingConvention/gcloaded_cache.ll
@@ -0,0 +1,45 @@
+; RUN: if [ %llvmver -lt 17 ]; then %opt < %s %loadEnzyme -enzyme -enzyme-preopt=false -enzyme-julia-addr-load -mem2reg -simplifycfg -adce -S | FileCheck %s; fi
+
+source_filename = "start"
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128-ni:10:11:12:13"
+target triple = "x86_64-linux-gnu"
+
+declare noundef nonnull {} addrspace(10)* addrspace(13)* @julia.gc_loaded({} addrspace(10)* nocapture noundef nonnull readnone, {} addrspace(10)** noundef nonnull readnone) local_unnamed_addr #1
+
+define double @f({} addrspace(10)** addrspace(11)* %slot_ptr, {} addrspace(10)* %obj1, {} addrspace(10)* %obj2, double %val) {
+entry:
+  ; Load the GC slot (type {} addrspace(10)**, AS 0 pointer pointing to AS 10)
+  %slot = load {} addrspace(10)**, {} addrspace(10)** addrspace(11)* %slot_ptr, align 8
+  
+  ; GC loaded calls
+  %191 = call {} addrspace(10)* addrspace(13)* @julia.gc_loaded({} addrspace(10)* %obj1, {} addrspace(10)** %slot)
+  %194 = call {} addrspace(10)* addrspace(13)* @julia.gc_loaded({} addrspace(10)* %obj2, {} addrspace(10)** %slot)
+  
+  ; Comparison
+  %.not7 = icmp eq {} addrspace(10)* addrspace(13)* %191, %194
+  br i1 %.not7, label %then, label %else
+
+then:
+  ; Active float work to force AD to track this branch
+  %mul = fmul double %val, %val
+  ret double %mul
+
+else:
+  %add = fadd double %val, 2.0
+  ret double %add
+}
+
+declare { i8*, double } @__enzyme_augmentfwd(...)
+
+define { i8*, double } @test({} addrspace(10)** addrspace(11)* %slot_ptr, {} addrspace(10)* %obj1, {} addrspace(10)* %obj2, double %val, double %dval) {
+entry:
+  %res = call { i8*, double } (...) @__enzyme_augmentfwd(double ({} addrspace(10)** addrspace(11)*, {} addrspace(10)*, {} addrspace(10)*, double)* @f, metadata !"enzyme_const", {} addrspace(10)** addrspace(11)* %slot_ptr, metadata !"enzyme_const", {} addrspace(10)* %obj1, metadata !"enzyme_const", {} addrspace(10)* %obj2, metadata !"enzyme_dup", double %val, double %dval)
+  ret { i8*, double } %res
+}
+
+attributes #1 = { nofree norecurse nosync nounwind speculatable willreturn "enzyme_nocache" "enzyme_shouldrecompute" }
+
+; We want to make sure the tape does NOT store the GC slot pointer ({} addrspace(10)**).
+; CHECK: define internal { i8*, double } @augmented_f({} addrspace(10)** addrspace(11)* %slot_ptr, {} addrspace(10)* %obj1, {} addrspace(10)* %obj2, double %val, double %"val'")
+; CHECK-NOT: store {} addrspace(10)**
+; CHECK: }