[llvm] [WebAssembly] Guard use of getSymbolName with isSymbol (PR #156105)

[Derek Schuff via llvm-commits]

https://github.com/dschuff created https://github.com/llvm/llvm-project/pull/156105

WebAssemblyRegStackfy checks for writes to the stack pointer to avoid
stackifying across them, but it wasn't prepared for other global_set
instructions (such as writes in addrspace 1).

Fixes #156055


>From 2e13be68916a123dce9ea300cd66e63dac8c86b0 Mon Sep 17 00:00:00 2001
From: Derek Schuff <dschuff at chromium.org>
Date: Fri, 29 Aug 2025 21:02:11 +0000
Subject: [PATCH] [WebAssembly] Guard use of getSymbolName with isSymbol

WebAssemblyRegStackfy checks for writes to the stack pointer to avoid
stackifying across them, but it wasn't prepared for other global_set
instructions (such as writes in addrspace 1).

Fixes #156055
---
 .../Target/WebAssembly/WebAssemblyRegStackify.cpp |  3 ++-
 llvm/test/CodeGen/WebAssembly/global-set.ll       | 15 +++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp
index bc91c6424b63e..08ca20b5eef6e 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp
@@ -247,7 +247,8 @@ static void query(const MachineInstr &MI, bool &Read, bool &Write,
   // Check for writes to __stack_pointer global.
   if ((MI.getOpcode() == WebAssembly::GLOBAL_SET_I32 ||
        MI.getOpcode() == WebAssembly::GLOBAL_SET_I64) &&
-      strcmp(MI.getOperand(0).getSymbolName(), "__stack_pointer") == 0)
+      MI.getOperand(0).isSymbol() &&
+      !strcmp(MI.getOperand(0).getSymbolName(), "__stack_pointer"))
     StackPointer = true;
 
   // Analyze calls.
diff --git a/llvm/test/CodeGen/WebAssembly/global-set.ll b/llvm/test/CodeGen/WebAssembly/global-set.ll
index 7db374528fe9b..f76006c2863b2 100644
--- a/llvm/test/CodeGen/WebAssembly/global-set.ll
+++ b/llvm/test/CodeGen/WebAssembly/global-set.ll
@@ -45,6 +45,21 @@ define void @set_f64_global(double %v) {
   ret void
 }
 
+declare i32 @get_i32()
+define i32 @testFunc() {
+; CHECK-LABEL: testFunc:
+; CHECK-NEXT: .functype
+; CHECK-NEXT: .local
+; CHECK-NEXT: call get_i32
+; CHECK-NEXT: local.tee
+; CHECK-NEXT: global.set i32_global
+; CHECK-NEXT: local.get
+; CHECK-NEXT: end_function
+  %1 = call i32 @get_i32()
+  store i32 %1, ptr addrspace(1) @i32_global
+  ret i32 %1
+}
+
 ; CHECK: .globaltype i32_global, i32
 ; CHECK: .globl i32_global
 ; CHECK-LABEL: i32_global: