[llvm] [Analysis] Attribute Range should not prevent tail call optimization (PR #91122)

Jinsong Ji via llvm-commits llvm-commits at lists.llvm.org
Mon May 6 17:25:37 PDT 2024


https://github.com/jsji updated https://github.com/llvm/llvm-project/pull/91122

>From eead1a5d9e8686e02082e3e6c2221f88a6ce1580 Mon Sep 17 00:00:00 2001
From: Jinsong Ji <jinsong.ji at intel.com>
Date: Sat, 4 May 2024 20:42:54 -0700
Subject: [PATCH 1/5] Remove Range attr when comparing for tailcall

---
 llvm/lib/CodeGen/Analysis.cpp | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/llvm/lib/CodeGen/Analysis.cpp b/llvm/lib/CodeGen/Analysis.cpp
index af7643d93591f7..e693cdbd0ccc1c 100644
--- a/llvm/lib/CodeGen/Analysis.cpp
+++ b/llvm/lib/CodeGen/Analysis.cpp
@@ -593,9 +593,10 @@ bool llvm::attributesPermitTailCall(const Function *F, const Instruction *I,
 
   // Following attributes are completely benign as far as calling convention
   // goes, they shouldn't affect whether the call is a tail call.
-  for (const auto &Attr : {Attribute::Alignment, Attribute::Dereferenceable,
-                           Attribute::DereferenceableOrNull, Attribute::NoAlias,
-                           Attribute::NonNull, Attribute::NoUndef}) {
+  for (const auto &Attr :
+       {Attribute::Alignment, Attribute::Dereferenceable,
+        Attribute::DereferenceableOrNull, Attribute::NoAlias,
+        Attribute::NonNull, Attribute::NoUndef, Attribute::Range}) {
     CallerAttrs.removeAttribute(Attr);
     CalleeAttrs.removeAttribute(Attr);
   }

>From b07946925570ba5996316f7d94d2617f2b0c89de Mon Sep 17 00:00:00 2001
From: Jinsong Ji <jinsong.ji at intel.com>
Date: Sun, 5 May 2024 06:39:14 -0700
Subject: [PATCH 2/5] Add test for testcall with range

---
 llvm/test/CodeGen/X86/tailcall-range.ll | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 llvm/test/CodeGen/X86/tailcall-range.ll

diff --git a/llvm/test/CodeGen/X86/tailcall-range.ll b/llvm/test/CodeGen/X86/tailcall-range.ll
new file mode 100644
index 00000000000000..1f7712d2494326
--- /dev/null
+++ b/llvm/test/CodeGen/X86/tailcall-range.ll
@@ -0,0 +1,23 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 4
+; RUN: opt -passes=ipsccp -S -mtriple=x86_64-linux < %s | llc -mtriple=x86_64-linux | FileCheck %s
+
+define i32 @foo(ptr %this, ...) {
+; CHECK-LABEL: foo:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    movzbl 0, %eax
+; CHECK-NEXT:    retq
+entry:
+  %call = load volatile i1, ptr null, align 1
+  %spec.select = zext i1 %call to i32
+  ret i32 %spec.select
+}
+
+define i32 @bar(ptr %this, ...) {
+; CHECK-LABEL: bar:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    xorl %edi, %edi
+; CHECK-NEXT:    jmp foo at PLT # TAILCALL
+entry:
+  %4 = musttail call i32 (ptr, ...) @foo(ptr null, ...)
+  ret i32 %4
+}

>From 6b78e6381caa6603446f78d7efbf43c79c53aac1 Mon Sep 17 00:00:00 2001
From: Jinsong Ji <jinsong.ji at intel.com>
Date: Sun, 5 May 2024 19:20:19 -0700
Subject: [PATCH 3/5] Update Attr in TargetLowering as well

---
 llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 336d89fbcf638e..9ec3ac4f99915e 100644
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -62,9 +62,10 @@ bool TargetLowering::isInTailCallPosition(SelectionDAG &DAG, SDNode *Node,
   // the return. Ignore following attributes because they don't affect the
   // call sequence.
   AttrBuilder CallerAttrs(F.getContext(), F.getAttributes().getRetAttrs());
-  for (const auto &Attr : {Attribute::Alignment, Attribute::Dereferenceable,
-                           Attribute::DereferenceableOrNull, Attribute::NoAlias,
-                           Attribute::NonNull, Attribute::NoUndef})
+  for (const auto &Attr :
+       {Attribute::Alignment, Attribute::Dereferenceable,
+        Attribute::DereferenceableOrNull, Attribute::NoAlias,
+        Attribute::NonNull, Attribute::NoUndef, Attribute::Range})
     CallerAttrs.removeAttribute(Attr);
 
   if (CallerAttrs.hasAttributes())

>From c0ab0a945139ee56accd8ac2f9bff477fc49e1d9 Mon Sep 17 00:00:00 2001
From: Jinsong Ji <jinsong.ji at intel.com>
Date: Mon, 6 May 2024 07:20:23 -0700
Subject: [PATCH 4/5] Update tests

---
 llvm/test/CodeGen/X86/tailcall-range.ll | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/llvm/test/CodeGen/X86/tailcall-range.ll b/llvm/test/CodeGen/X86/tailcall-range.ll
index 1f7712d2494326..cb44540662d11d 100644
--- a/llvm/test/CodeGen/X86/tailcall-range.ll
+++ b/llvm/test/CodeGen/X86/tailcall-range.ll
@@ -1,7 +1,7 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 4
-; RUN: opt -passes=ipsccp -S -mtriple=x86_64-linux < %s | llc -mtriple=x86_64-linux | FileCheck %s
+; RUN: llc -mtriple=x86_64-linux < %s | FileCheck %s
 
-define i32 @foo(ptr %this, ...) {
+define range(i32 0, 2) i32 @foo(ptr %this, ...) {
 ; CHECK-LABEL: foo:
 ; CHECK:       # %bb.0: # %entry
 ; CHECK-NEXT:    movzbl 0, %eax
@@ -12,7 +12,7 @@ entry:
   ret i32 %spec.select
 }
 
-define i32 @bar(ptr %this, ...) {
+define range(i32 0, 2) i32 @bar(ptr %this, ...) {
 ; CHECK-LABEL: bar:
 ; CHECK:       # %bb.0: # %entry
 ; CHECK-NEXT:    xorl %edi, %edi

>From 7d3aa09760441f94b98f324ee8349f1c1bc76ea3 Mon Sep 17 00:00:00 2001
From: Jinsong Ji <jinsong.ji at intel.com>
Date: Mon, 6 May 2024 17:25:18 -0700
Subject: [PATCH 5/5] Revert "Update Attr in TargetLowering as well"

This reverts commit 6b78e6381caa6603446f78d7efbf43c79c53aac1.
---
 llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 9ec3ac4f99915e..336d89fbcf638e 100644
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -62,10 +62,9 @@ bool TargetLowering::isInTailCallPosition(SelectionDAG &DAG, SDNode *Node,
   // the return. Ignore following attributes because they don't affect the
   // call sequence.
   AttrBuilder CallerAttrs(F.getContext(), F.getAttributes().getRetAttrs());
-  for (const auto &Attr :
-       {Attribute::Alignment, Attribute::Dereferenceable,
-        Attribute::DereferenceableOrNull, Attribute::NoAlias,
-        Attribute::NonNull, Attribute::NoUndef, Attribute::Range})
+  for (const auto &Attr : {Attribute::Alignment, Attribute::Dereferenceable,
+                           Attribute::DereferenceableOrNull, Attribute::NoAlias,
+                           Attribute::NonNull, Attribute::NoUndef})
     CallerAttrs.removeAttribute(Attr);
 
   if (CallerAttrs.hasAttributes())



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