[llvm] Default stack alignment of X86 Hurd to 16 bytes (PR #158454)

[Brad Smith via llvm-commits]

https://github.com/brad0 updated https://github.com/llvm/llvm-project/pull/158454

>From 3ac1ed9d6d47b78bf5d2cb3e6397fa703b048552 Mon Sep 17 00:00:00 2001
From: Brad Smith <brad at comstyle.com>
Date: Sun, 14 Sep 2025 00:18:02 -0400
Subject: [PATCH] Default stack alignment of X86 Hurd to 16 bytes

---
 llvm/lib/Target/X86/X86Subtarget.cpp  | 5 +++--
 llvm/lib/Target/X86/X86Subtarget.h    | 1 +
 llvm/test/CodeGen/X86/stack-align2.ll | 5 +++++
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/Target/X86/X86Subtarget.cpp b/llvm/lib/Target/X86/X86Subtarget.cpp
index fd5f34b60efb8..66d9e74855bcf 100644
--- a/llvm/lib/Target/X86/X86Subtarget.cpp
+++ b/llvm/lib/Target/X86/X86Subtarget.cpp
@@ -284,12 +284,13 @@ void X86Subtarget::initSubtargetFeatures(StringRef CPU, StringRef TuneCPU,
     reportFatalUsageError("64-bit code requested on a subtarget that doesn't "
                           "support it!");
 
-  // Stack alignment is 16 bytes on Darwin, Linux, kFreeBSD, and for all
+  // Stack alignment is 16 bytes on Darwin, Linux, kFreeBSD, Hurd and for all
   // 64-bit targets.  On Solaris (32-bit), stack alignment is 4 bytes
   // following the i386 psABI, while on Illumos it is always 16 bytes.
   if (StackAlignOverride)
     stackAlignment = *StackAlignOverride;
-  else if (isTargetDarwin() || isTargetLinux() || isTargetKFreeBSD() || Is64Bit)
+  else if (isTargetDarwin() || isTargetLinux() || isTargetKFreeBSD() ||
+           isTargetHurd() || Is64Bit)
     stackAlignment = Align(16);
 
   // Consume the vector width attribute or apply any target specific limit.
diff --git a/llvm/lib/Target/X86/X86Subtarget.h b/llvm/lib/Target/X86/X86Subtarget.h
index fa3f3b59741df..7cee0ee4b046e 100644
--- a/llvm/lib/Target/X86/X86Subtarget.h
+++ b/llvm/lib/Target/X86/X86Subtarget.h
@@ -291,6 +291,7 @@ class X86Subtarget final : public X86GenSubtargetInfo {
 
   bool isTargetLinux() const { return TargetTriple.isOSLinux(); }
   bool isTargetKFreeBSD() const { return TargetTriple.isOSKFreeBSD(); }
+  bool isTargetHurd() const { return TargetTriple.isOSHurd(); }
   bool isTargetGlibc() const { return TargetTriple.isOSGlibc(); }
   bool isTargetAndroid() const { return TargetTriple.isAndroid(); }
   bool isTargetMCU() const { return TargetTriple.isOSIAMCU(); }
diff --git a/llvm/test/CodeGen/X86/stack-align2.ll b/llvm/test/CodeGen/X86/stack-align2.ll
index 095a9090ed08f..5d1d32225c2cb 100644
--- a/llvm/test/CodeGen/X86/stack-align2.ll
+++ b/llvm/test/CodeGen/X86/stack-align2.ll
@@ -1,10 +1,12 @@
 ; RUN: llc < %s -mcpu=generic -mtriple=i386-linux | FileCheck %s -check-prefix=LINUX-I386
 ; RUN: llc < %s -mcpu=generic -mtriple=i386-kfreebsd | FileCheck %s -check-prefix=KFREEBSD-I386
+; RUN: llc < %s -mcpu=generic -mtriple=i386-hurd | FileCheck %s -check-prefix=HURD-I386
 ; RUN: llc < %s -mcpu=generic -mtriple=i386-netbsd | FileCheck %s -check-prefix=NETBSD-I386
 ; RUN: llc < %s -mcpu=generic -mtriple=i686-apple-darwin8 | FileCheck %s -check-prefix=DARWIN-I386
 ; RUN: llc < %s -mcpu=generic -mtriple=i386-pc-solaris2.11 | FileCheck %s -check-prefix=SOLARIS-I386
 ; RUN: llc < %s -mcpu=generic -mtriple=x86_64-linux | FileCheck %s -check-prefix=LINUX-X86_64
 ; RUN: llc < %s -mcpu=generic -mtriple=x86_64-kfreebsd | FileCheck %s -check-prefix=KFREEBSD-X86_64
+; RUN: llc < %s -mcpu=generic -mtriple=x86_64-hurd | FileCheck %s -check-prefix=HURD-X86_64
 ; RUN: llc < %s -mcpu=generic -mtriple=x86_64-netbsd | FileCheck %s -check-prefix=NETBSD-X86_64
 ; RUN: llc < %s -mcpu=generic -mtriple=x86_64-apple-darwin8 | FileCheck %s -check-prefix=DARWIN-X86_64
 ; RUN: llc < %s -mcpu=generic -mtriple=x86_64-pc-solaris2.11 | FileCheck %s -check-prefix=SOLARIS-X86_64
@@ -17,6 +19,7 @@ entry:
 ; LINUX-I386:     subl	$12, %esp
 ; KFREEBSD-I386:  subl	$12, %esp
 ; DARWIN-I386:    subl	$12, %esp
+; HURD-I386:      subl  $12, %esp
 ; NETBSD-I386-NOT:  subl	{{.*}}, %esp
 ; SOLARIS-I386-NOT: subl	{{.*}}, %esp
 
@@ -30,6 +33,8 @@ entry:
 ; SOLARIS-X86_64-NOT: subq	{{.*}}, %rsp
 ; KFREEBSD-X86_64:     pushq %{{.*}}
 ; KFREEBSD-X86_64-NOT: subq	{{.*}}, %rsp
+; HURD-X86_64:       pushq %{{.*}}
+; HURD-X86_64-NOT:   subq       {{.*}}, %rsp
 }
 
 declare void @test2()