[Transform] Clean up strlen loop idiom #132421
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@llvm/pr-subscribers-llvm-transforms Author: Henry Jiang (mustartt) ChangesAddress buildbot failure in https://lab.llvm.org/buildbot/#/builders/187/builds/4958 with expensive check enabled. We should bailout of modifying the CFG if the library functions are not emittable or disabled. Full diff: https://github.com/llvm/llvm-project/pull/132421.diff 5 Files Affected:
diff --git a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
index b91cdc0748581..7f92f5f65a972 100644
--- a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
@@ -1515,16 +1515,6 @@ bool LoopIdiomRecognize::runOnNoncountableLoop() {
recognizeShiftUntilLessThan() || recognizeAndInsertStrLen();
}
-/// Check if a Value is either a nullptr or a constant int zero
-static bool isZeroConstant(const Value *Val) {
- if (isa<ConstantPointerNull>(Val))
- return true;
- const ConstantInt *CmpZero = dyn_cast<ConstantInt>(Val);
- if (!CmpZero || !CmpZero->isZero())
- return false;
- return true;
-}
-
/// Check if the given conditional branch is based on the comparison between
/// a variable and zero, and if the variable is non-zero or zero (JmpOnZero is
/// true), the control yields to the loop entry. If the branch matches the
@@ -1540,7 +1530,8 @@ static Value *matchCondition(BranchInst *BI, BasicBlock *LoopEntry,
if (!Cond)
return nullptr;
- if (!isZeroConstant(Cond->getOperand(1)))
+ const ConstantInt *CmpZero = dyn_cast<ConstantInt>(Cond->getOperand(1));
+ if (!CmpZero || !CmpZero->isZero())
return nullptr;
BasicBlock *TrueSucc = BI->getSuccessor(0);
@@ -1656,11 +1647,7 @@ class StrlenVerifier {
if (!Ev)
return false;
- LLVM_DEBUG({
- dbgs() << "loop exit phi scev: ";
- Ev->print(dbgs());
- dbgs() << "\n";
- });
+ LLVM_DEBUG(dbgs() << "loop exit phi scev: " << *Ev << "\n");
// Since we verified that the loop trip count will be a valid strlen
// idiom, we can expand all lcssa phi with {n,+,1} as (n + strlen) and use
@@ -1763,6 +1750,18 @@ bool LoopIdiomRecognize::recognizeAndInsertStrLen() {
BasicBlock *Preheader = CurLoop->getLoopPreheader();
BasicBlock *LoopExitBB = CurLoop->getExitBlock();
+ if (Verifier.OpWidth == 8) {
+ if (DisableLIRP::Strlen)
+ return false;
+ if (!isLibFuncEmittable(Preheader->getModule(), TLI, LibFunc_strlen))
+ return false;
+ } else {
+ if (DisableLIRP::Wcslen)
+ return false;
+ if (!isLibFuncEmittable(Preheader->getModule(), TLI, LibFunc_wcslen))
+ return false;
+ }
+
IRBuilder<> Builder(Preheader->getTerminator());
SCEVExpander Expander(*SE, Preheader->getModule()->getDataLayout(),
"strlen_idiom");
@@ -1772,16 +1771,8 @@ bool LoopIdiomRecognize::recognizeAndInsertStrLen() {
Value *StrLenFunc = nullptr;
if (Verifier.OpWidth == 8) {
- if (DisableLIRP::Strlen)
- return false;
- if (!isLibFuncEmittable(Preheader->getModule(), TLI, LibFunc_strlen))
- return false;
StrLenFunc = emitStrLen(MaterialzedBase, Builder, *DL, TLI);
} else {
- if (DisableLIRP::Wcslen)
- return false;
- if (!isLibFuncEmittable(Preheader->getModule(), TLI, LibFunc_wcslen))
- return false;
StrLenFunc = emitWcsLen(MaterialzedBase, Builder, *DL, TLI);
}
assert(StrLenFunc && "Failed to emit strlen function.");
diff --git a/llvm/test/Transforms/LoopIdiom/strlen-not-emittable.ll b/llvm/test/Transforms/LoopIdiom/strlen-not-emittable.ll
index 0be76cbd42a72..00fbe89846a30 100644
--- a/llvm/test/Transforms/LoopIdiom/strlen-not-emittable.ll
+++ b/llvm/test/Transforms/LoopIdiom/strlen-not-emittable.ll
@@ -1,4 +1,4 @@
-; RUN: opt -passes='loop(loop-idiom),verify' < %s -S | FileCheck %s
+; RUN: opt -passes='loop(loop-idiom)' < %s -S | FileCheck %s
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
diff --git a/llvm/test/Transforms/LoopIdiom/strlen.ll b/llvm/test/Transforms/LoopIdiom/strlen.ll
index 137a17f541cd4..c1141177c659f 100644
--- a/llvm/test/Transforms/LoopIdiom/strlen.ll
+++ b/llvm/test/Transforms/LoopIdiom/strlen.ll
@@ -1,5 +1,5 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
-; RUN: opt -passes='loop(loop-idiom),verify' < %s -S | FileCheck %s
+; RUN: opt -passes='loop(loop-idiom)' < %s -S | FileCheck %s
declare void @other()
declare void @use(ptr)
diff --git a/llvm/test/Transforms/LoopIdiom/wcslen16.ll b/llvm/test/Transforms/LoopIdiom/wcslen16.ll
index d3b0b8d208cd8..8be51869f1f2e 100644
--- a/llvm/test/Transforms/LoopIdiom/wcslen16.ll
+++ b/llvm/test/Transforms/LoopIdiom/wcslen16.ll
@@ -1,5 +1,5 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
-; RUN: opt -passes='loop(loop-idiom),verify' < %s -S | FileCheck %s
+; RUN: opt -passes='loop(loop-idiom)' < %s -S | FileCheck %s
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
diff --git a/llvm/test/Transforms/LoopIdiom/wcslen32.ll b/llvm/test/Transforms/LoopIdiom/wcslen32.ll
index 488afff86c245..2c7ceb4d187e6 100644
--- a/llvm/test/Transforms/LoopIdiom/wcslen32.ll
+++ b/llvm/test/Transforms/LoopIdiom/wcslen32.ll
@@ -1,5 +1,5 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
-; RUN: opt -passes='loop(loop-idiom),verify' < %s -S | FileCheck %s
+; RUN: opt -passes='loop(loop-idiom)' < %s -S | FileCheck %s
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
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| @@ -1,4 +1,4 @@ | |||
| ; RUN: opt -passes='loop(loop-idiom),verify' < %s -S | FileCheck %s | |||
There was a problem hiding this comment.
Its redundant:
#131412 (comment)
I also verified that verify is already scheduled at the end of the pipeline.
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| @@ -1540,7 +1530,8 @@ static Value *matchCondition(BranchInst *BI, BasicBlock *LoopEntry, | |||
| if (!Cond) | |||
| return nullptr; | |||
|
|
|||
| if (!isZeroConstant(Cond->getOperand(1))) | |||
| const ConstantInt *CmpZero = dyn_cast<ConstantInt>(Cond->getOperand(1)); | |||
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Suggested change
| const ConstantInt *CmpZero = dyn_cast<ConstantInt>(Cond->getOperand(1)); | |
| auto *CmpZero = dyn_cast<ConstantInt>(Cond->getOperand(1)); |
Prefer auto with dyn_cast.
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/18/builds/13320 Here is the relevant piece of the build log for the reference |
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We should bailout of modifying the CFG if the library functions are not emittable or disabled.
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We should bailout of modifying the CFG if the library functions are not emittable or disabled.
Address buildbot failure in https://lab.llvm.org/buildbot/#/builders/187/builds/4958 with expensive check enabled.