[llvm] d079dbc - [CodeGen] Basic block sections should take precendence over splitting.

[Snehasish Kumar via llvm-commits]

Author: Snehasish Kumar
Date: 2021-02-11T11:14:10-08:00
New Revision: d079dbc591899159925a1fe10b081fa0f6bb61bd

URL: https://github.com/llvm/llvm-project/commit/d079dbc591899159925a1fe10b081fa0f6bb61bd
DIFF: https://github.com/llvm/llvm-project/commit/d079dbc591899159925a1fe10b081fa0f6bb61bd.diff

LOG: [CodeGen] Basic block sections should take precendence over splitting.

The use of basic block sections should take precedence over the machine
function splitting pass. Since they use the same underlying mechanism
they are kept exclusive. Updated the tests to check that split machine
functions is overridden by all flavours of basic block sections.

Differential Revision: https://reviews.llvm.org/D96392

Added: 
    

Modified: 
    llvm/lib/CodeGen/TargetPassConfig.cpp
    llvm/test/CodeGen/X86/basic-block-sections-labels.ll
    llvm/test/CodeGen/X86/basic-block-sections-list.ll
    llvm/test/CodeGen/X86/basic-block-sections.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/CodeGen/TargetPassConfig.cpp b/llvm/lib/CodeGen/TargetPassConfig.cpp
index e844d03854e2..30b58e6c7062 100644
--- a/llvm/lib/CodeGen/TargetPassConfig.cpp
+++ b/llvm/lib/CodeGen/TargetPassConfig.cpp
@@ -1187,12 +1187,14 @@ void TargetPassConfig::addMachinePasses() {
   }
 
   // Machine function splitter uses the basic block sections feature. Both
-  // cannot be enabled at the same time.
-  if (TM->Options.EnableMachineFunctionSplitter ||
-      EnableMachineFunctionSplitter) {
-    addPass(createMachineFunctionSplitterPass());
-  } else if (TM->getBBSectionsType() != llvm::BasicBlockSection::None) {
+  // cannot be enabled at the same time. Basic block sections takes precedence.
+  // FIXME: In principle, BasicBlockSection::Labels and splitting can used
+  // together. Update this check once we have addressed any issues.
+  if (TM->getBBSectionsType() != llvm::BasicBlockSection::None) {
     addPass(llvm::createBasicBlockSectionsPass(TM->getBBSectionsFuncListBuf()));
+  } else if (TM->Options.EnableMachineFunctionSplitter ||
+             EnableMachineFunctionSplitter) {
+    addPass(createMachineFunctionSplitterPass());
   }
 
   // Add passes that directly emit MI after all other MI passes.

diff  --git a/llvm/test/CodeGen/X86/basic-block-sections-labels.ll b/llvm/test/CodeGen/X86/basic-block-sections-labels.ll
index 8a76fef672eb..f447834de823 100644
--- a/llvm/test/CodeGen/X86/basic-block-sections-labels.ll
+++ b/llvm/test/CodeGen/X86/basic-block-sections-labels.ll
@@ -1,6 +1,7 @@
 ; Check the basic block sections labels option
 ; RUN: llc < %s -mtriple=x86_64 -function-sections -unique-section-names=true -basic-block-sections=labels | FileCheck %s --check-prefix=UNIQ
 ; RUN: llc < %s -mtriple=x86_64 -function-sections -unique-section-names=false -basic-block-sections=labels | FileCheck %s --check-prefix=NOUNIQ
+; RUN: llc < %s -mtriple=x86_64 -function-sections -unique-section-names=true -basic-block-sections=labels -split-machine-functions | FileCheck %s --check-prefix=UNIQ
 
 define void @_Z3bazb(i1 zeroext) personality i32 (...)* @__gxx_personality_v0 {
   br i1 %0, label %2, label %7

diff  --git a/llvm/test/CodeGen/X86/basic-block-sections-list.ll b/llvm/test/CodeGen/X86/basic-block-sections-list.ll
index 8d788ffb1234..ab5abdcd01c1 100644
--- a/llvm/test/CodeGen/X86/basic-block-sections-list.ll
+++ b/llvm/test/CodeGen/X86/basic-block-sections-list.ll
@@ -1,6 +1,7 @@
 ; Check the basic block sections list option.
 ; RUN: echo '!_Z3foob' > %t
 ; RUN: llc < %s -mtriple=x86_64-pc-linux -function-sections -basic-block-sections=%t -unique-basic-block-section-names | FileCheck %s -check-prefix=LINUX-SECTIONS
+; RUN: llc < %s -mtriple=x86_64-pc-linux -function-sections -basic-block-sections=%t -unique-basic-block-section-names -split-machine-functions | FileCheck %s -check-prefix=LINUX-SECTIONS
 
 define i32 @_Z3foob(i1 zeroext %0) nounwind {
   %2 = alloca i32, align 4

diff  --git a/llvm/test/CodeGen/X86/basic-block-sections.ll b/llvm/test/CodeGen/X86/basic-block-sections.ll
index 7b93076eb434..a6dc6e5758ea 100644
--- a/llvm/test/CodeGen/X86/basic-block-sections.ll
+++ b/llvm/test/CodeGen/X86/basic-block-sections.ll
@@ -1,5 +1,6 @@
 ; RUN: llc < %s -mtriple=x86_64-pc-linux -function-sections -basic-block-sections=all -unique-basic-block-section-names | FileCheck %s -check-prefix=LINUX-SECTIONS
 ; RUN: llc < %s -mtriple=i386-unknown-linux-gnu  -function-sections -basic-block-sections=all -unique-basic-block-section-names | FileCheck %s -check-prefix=LINUX-SECTIONS
+; RUN: llc < %s -mtriple=x86_64-pc-linux -function-sections -basic-block-sections=all -unique-basic-block-section-names -split-machine-functions | FileCheck %s -check-prefix=LINUX-SECTIONS
 
 define void @_Z3bazb(i1 zeroext) nounwind {
   %2 = alloca i8, align 1