[PATCH] D43821: [SemaCXX] _Pragma("clang optimize off") not affecting lambda.
Carlos Alberto Enciso via Phabricator via cfe-commits
cfe-commits at lists.llvm.org
Tue Feb 27 06:39:28 PST 2018
CarlosAlbertoEnciso created this revision.
CarlosAlbertoEnciso added reviewers: rsmith, erichkeane, andreadb.
CarlosAlbertoEnciso added a project: clang.
Declaring "_Pragma("clang optimize off")" before the body of a
function with a lambda leads to the lambda functions in the body
not being affected.
For the below test:
_Pragma("clang optimize off")
void foo(int p) {
auto lambda = [&p]() { ++p; };
lambda();
}
_Pragma("clang optimize on")
At -O1 the attributes for the 'foo' function are:
attributes #0 = { noinline nounwind optnone uwtable ... }
At -O1 the attributes for the lambda function are:
attributes #1 = { inlinehint norecurse nounwind uwtable ... }
The incorrect attribute causes the lambda function to be considered
for inlining ignoring the given _Pragma.
Repository:
rC Clang
https://reviews.llvm.org/D43821
Files:
lib/Sema/SemaDecl.cpp
test/CodeGenCXX/optnone-pragma-optimize-off.cpp
Index: test/CodeGenCXX/optnone-pragma-optimize-off.cpp
===================================================================
--- test/CodeGenCXX/optnone-pragma-optimize-off.cpp
+++ test/CodeGenCXX/optnone-pragma-optimize-off.cpp
@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 %s -triple %itanium_abi_triple -O1 -disable-llvm-passes -emit-llvm -o - | FileCheck %s
+
+// Test the attributes for the lambda function contains 'optnone' as result of
+// the _Pragma("clang optimize off").
+
+_Pragma("clang optimize off")
+
+void foo(int p) {
+ auto lambda = [&p]() { ++p; };
+ lambda();
+ // CHECK: define {{.*}} @"_ZZ3fooiENK3$_0clEv"({{.*}}) #[[LAMBDA_ATR:[0-9]+]]
+}
+
+_Pragma("clang optimize on")
+
+// CHECK: attributes #[[LAMBDA_ATR]] = { {{.*}} optnone {{.*}} }
Index: lib/Sema/SemaDecl.cpp
===================================================================
--- lib/Sema/SemaDecl.cpp
+++ lib/Sema/SemaDecl.cpp
@@ -12593,6 +12593,10 @@
FD->setBody(Body);
FD->setWillHaveBody(false);
+ // This represents the function body for the lambda function, check if we
+ // have to apply optnone due to a pragma.
+ AddRangeBasedOptnone(FD);
+
if (getLangOpts().CPlusPlus14) {
if (!FD->isInvalidDecl() && Body && !FD->isDependentContext() &&
FD->getReturnType()->isUndeducedType()) {
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