[PATCH] D86841: [clang] Adds noprogress attribute deduction for infinite loops
atmnpatel updated this revision to Diff 288818.
atmnpatel added a comment.
Fixed comment in C++ test.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D86841/new/
https://reviews.llvm.org/D86841
Files:
clang/lib/CodeGen/CGLoopInfo.cpp
clang/lib/CodeGen/CGLoopInfo.h
clang/lib/CodeGen/CGStmt.cpp
clang/test/CodeGen/attr-noprogress.c
clang/test/CodeGen/attr-noprogress.cpp
Index: clang/test/CodeGen/attr-noprogress.cpp
===
--- /dev/null
+++ clang/test/CodeGen/attr-noprogress.cpp
@@ -0,0 +1,55 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --check-attributes
+// RUN: %clang_cc1 -S -emit-llvm %s -o - | FileCheck %s
+
+// CHECK: Function Attrs: noinline nounwind optnone noprogress
+// CHECK-LABEL: define {{[^@]+}}@_Z1fv
+// CHECK-SAME: () [[ATTR0:#.*]] {
+// CHECK-NEXT: entry:
+// CHECK-NEXT:br label [[FOR_COND:%.*]]
+// CHECK: for.cond:
+// CHECK-NEXT:br i1 true, label [[FOR_BODY:%.*]], label [[FOR_END:%.*]]
+// CHECK: for.body:
+// CHECK-NEXT:br label [[FOR_COND]], !llvm.loop [[LOOP2:!.]]
+// CHECK: for.end:
+// CHECK-NEXT:ret void
+//
+void f() {
+ for (; 1;) {
+ }
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone noprogress
+// CHECK-LABEL: define {{[^@]+}}@_Z1wv
+// CHECK-SAME: () [[ATTR0]] {
+// CHECK-NEXT: entry:
+// CHECK-NEXT:br label [[WHILE_BODY:%.*]]
+// CHECK: while.body:
+// CHECK-NEXT:br label [[WHILE_BODY]], !llvm.loop [[LOOP4:!.]]
+//
+void w() {
+ while (1) {
+ }
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone noprogress
+// CHECK-LABEL: define {{[^@]+}}@_Z1dv
+// CHECK-SAME: () [[ATTR0]] {
+// CHECK-NEXT: entry:
+// CHECK-NEXT:br label [[DO_BODY:%.*]]
+// CHECK: do.body:
+// CHECK-NEXT:br label [[DO_COND:%.*]]
+// CHECK: do.cond:
+// CHECK-NEXT:br i1 true, label [[DO_BODY]], label [[DO_END:%.*]], !llvm.loop [[LOOP5:!.]]
+// CHECK: do.end:
+// CHECK-NEXT:ret void
+//
+void d() {
+ do {
+
+ } while (1);
+}
+
+// CHECK: [[LOOP2]] = distinct !{[[LOOP2]], [[LOOP_MD:!.]]}
+// CHECK: [[LOOP_MD]] = !{!"llvm.loop.noprogress"}
+// CHECK: [[LOOP4]] = distinct !{[[LOOP4]], [[LOOP_MD]]}
+// CHECK: [[LOOP5]] = distinct !{[[LOOP5]], [[LOOP_MD]]}
Index: clang/test/CodeGen/attr-noprogress.c
===
--- /dev/null
+++ clang/test/CodeGen/attr-noprogress.c
@@ -0,0 +1,52 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --check-attributes
+// RUN: %clang_cc1 -S -emit-llvm %s -o - | FileCheck %s
+
+// CHECK: Function Attrs: noinline nounwind optnone noprogress
+// CHECK-LABEL: @f(
+// CHECK-NEXT: entry:
+// CHECK-NEXT:br label [[FOR_COND:%.*]]
+// CHECK: for.cond:
+// CHECK-NEXT:br i1 true, label [[FOR_BODY:%.*]], label [[FOR_END:%.*]]
+// CHECK: for.body:
+// CHECK-NEXT:br label [[FOR_COND]], !llvm.loop [[LOOP2:!.]]
+// CHECK: for.end:
+// CHECK-NEXT:ret void
+//
+void f() {
+ for (; 1;) {
+ }
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone noprogress
+// CHECK-LABEL: @w(
+// CHECK-NEXT: entry:
+// CHECK-NEXT:br label [[WHILE_BODY:%.*]]
+// CHECK: while.body:
+// CHECK-NEXT:br label [[WHILE_BODY]], !llvm.loop [[LOOP4:!.]]
+//
+void w() {
+ while (1) {
+ }
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone noprogress
+// CHECK-LABEL: @d(
+// CHECK-NEXT: entry:
+// CHECK-NEXT:br label [[DO_BODY:%.*]]
+// CHECK: do.body:
+// CHECK-NEXT:br label [[DO_COND:%.*]]
+// CHECK: do.cond:
+// CHECK-NEXT:br i1 true, label [[DO_BODY]], label [[DO_END:%.*]], !llvm.loop [[LOOP5:!.]]
+// CHECK: do.end:
+// CHECK-NEXT:ret void
+//
+void d() {
+ do {
+
+ } while (1);
+}
+
+// CHECK: [[LOOP2]] = distinct !{[[LOOP2]], [[LOOP_MD:!.]]}
+// CHECK: [[LOOP_MD]] = !{!"llvm.loop.noprogress"}
+// CHECK: [[LOOP4]] = distinct !{[[LOOP4]], [[LOOP_MD]]}
+// CHECK: [[LOOP5]] = distinct !{[[LOOP5]], [[LOOP_MD]]}
Index: clang/lib/CodeGen/CGStmt.cpp
===
--- clang/lib/CodeGen/CGStmt.cpp
+++ clang/lib/CodeGen/CGStmt.cpp
@@ -736,10 +736,26 @@
JumpDest LoopHeader = getJumpDestInCurrentScope("while.cond");
EmitBlock(LoopHeader.getBlock());
+ // Evaluate the conditional in the while header. C99 6.8.5.1: The
+ // evaluation of the controlling expression takes place before each
+ // execution of the loop body.
+ llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
+
+ // while(1) is common, avoid extra exit blocks. Be sure
+ // to correctly handle break/continue though.
+ bool EmitBoolCondBranch = true;
+ bool NoProgress = false;
+ if (llvm::ConstantInt *C = dyn_cast(BoolCondVal))
+if (C->isOne()) {
+ EmitBoolCondBranch = false;
+ CurFn->addFnAttr(llvm::Attribute::NoProgress);
+
[PATCH] D86841: [clang] Adds noprogress attribute deduction for infinite loops
atmnpatel updated this revision to Diff 288817.
atmnpatel edited the summary of this revision.
atmnpatel added a comment.
Sorry, Fixed the test, added a C++ test. I checked the C++, OpenCL C, and
OpenCL C++ specs and couldn't find anything that diverged from C spec in this
regard, but none of them explicitly stated this behavior either.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D86841/new/
https://reviews.llvm.org/D86841
Files:
clang/lib/CodeGen/CGLoopInfo.cpp
clang/lib/CodeGen/CGLoopInfo.h
clang/lib/CodeGen/CGStmt.cpp
clang/test/CodeGen/attr-noprogress.c
clang/test/CodeGen/attr-noprogress.cpp
Index: clang/test/CodeGen/attr-noprogress.cpp
===
--- /dev/null
+++ clang/test/CodeGen/attr-noprogress.cpp
@@ -0,0 +1,55 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --function-signature --check-attributes --force-update
+// RUN: %clang_cc1 -S -emit-llvm %s -o - | FileCheck %s
+
+// CHECK: Function Attrs: noinline nounwind optnone noprogress
+// CHECK-LABEL: define {{[^@]+}}@_Z1fv
+// CHECK-SAME: () [[ATTR0:#.*]] {
+// CHECK-NEXT: entry:
+// CHECK-NEXT:br label [[FOR_COND:%.*]]
+// CHECK: for.cond:
+// CHECK-NEXT:br i1 true, label [[FOR_BODY:%.*]], label [[FOR_END:%.*]]
+// CHECK: for.body:
+// CHECK-NEXT:br label [[FOR_COND]], !llvm.loop [[LOOP2:!.]]
+// CHECK: for.end:
+// CHECK-NEXT:ret void
+//
+void f() {
+ for (; 1;) {
+ }
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone noprogress
+// CHECK-LABEL: define {{[^@]+}}@_Z1wv
+// CHECK-SAME: () [[ATTR0]] {
+// CHECK-NEXT: entry:
+// CHECK-NEXT:br label [[WHILE_BODY:%.*]]
+// CHECK: while.body:
+// CHECK-NEXT:br label [[WHILE_BODY]], !llvm.loop [[LOOP4:!.]]
+//
+void w() {
+ while (1) {
+ }
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone noprogress
+// CHECK-LABEL: define {{[^@]+}}@_Z1dv
+// CHECK-SAME: () [[ATTR0]] {
+// CHECK-NEXT: entry:
+// CHECK-NEXT:br label [[DO_BODY:%.*]]
+// CHECK: do.body:
+// CHECK-NEXT:br label [[DO_COND:%.*]]
+// CHECK: do.cond:
+// CHECK-NEXT:br i1 true, label [[DO_BODY]], label [[DO_END:%.*]], !llvm.loop [[LOOP5:!.]]
+// CHECK: do.end:
+// CHECK-NEXT:ret void
+//
+void d() {
+ do {
+
+ } while (1);
+}
+
+// CHECK: [[LOOP2]] = distinct !{[[LOOP2]], [[LOOP_MD:!.]]}
+// CHECK: [[LOOP_MD]] = !{!"llvm.loop.noprogress"}
+// CHECK: [[LOOP4]] = distinct !{[[LOOP4]], [[LOOP_MD]]}
+// CHECK: [[LOOP5]] = distinct !{[[LOOP5]], [[LOOP_MD]]}
Index: clang/test/CodeGen/attr-noprogress.c
===
--- /dev/null
+++ clang/test/CodeGen/attr-noprogress.c
@@ -0,0 +1,52 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --check-attributes
+// RUN: %clang_cc1 -S -emit-llvm %s -o - | FileCheck %s
+
+// CHECK: Function Attrs: noinline nounwind optnone noprogress
+// CHECK-LABEL: @f(
+// CHECK-NEXT: entry:
+// CHECK-NEXT:br label [[FOR_COND:%.*]]
+// CHECK: for.cond:
+// CHECK-NEXT:br i1 true, label [[FOR_BODY:%.*]], label [[FOR_END:%.*]]
+// CHECK: for.body:
+// CHECK-NEXT:br label [[FOR_COND]], !llvm.loop [[LOOP2:!.]]
+// CHECK: for.end:
+// CHECK-NEXT:ret void
+//
+void f() {
+ for (; 1;) {
+ }
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone noprogress
+// CHECK-LABEL: @w(
+// CHECK-NEXT: entry:
+// CHECK-NEXT:br label [[WHILE_BODY:%.*]]
+// CHECK: while.body:
+// CHECK-NEXT:br label [[WHILE_BODY]], !llvm.loop [[LOOP4:!.]]
+//
+void w() {
+ while (1) {
+ }
+}
+
+// CHECK: Function Attrs: noinline nounwind optnone noprogress
+// CHECK-LABEL: @d(
+// CHECK-NEXT: entry:
+// CHECK-NEXT:br label [[DO_BODY:%.*]]
+// CHECK: do.body:
+// CHECK-NEXT:br label [[DO_COND:%.*]]
+// CHECK: do.cond:
+// CHECK-NEXT:br i1 true, label [[DO_BODY]], label [[DO_END:%.*]], !llvm.loop [[LOOP5:!.]]
+// CHECK: do.end:
+// CHECK-NEXT:ret void
+//
+void d() {
+ do {
+
+ } while (1);
+}
+
+// CHECK: [[LOOP2]] = distinct !{[[LOOP2]], [[LOOP_MD:!.]]}
+// CHECK: [[LOOP_MD]] = !{!"llvm.loop.noprogress"}
+// CHECK: [[LOOP4]] = distinct !{[[LOOP4]], [[LOOP_MD]]}
+// CHECK: [[LOOP5]] = distinct !{[[LOOP5]], [[LOOP_MD]]}
Index: clang/lib/CodeGen/CGStmt.cpp
===
--- clang/lib/CodeGen/CGStmt.cpp
+++ clang/lib/CodeGen/CGStmt.cpp
@@ -736,10 +736,26 @@
JumpDest LoopHeader = getJumpDestInCurrentScope("while.cond");
EmitBlock(LoopHeader.getBlock());
+ // Evaluate the conditional in the while header. C99 6.8.5.1: The
+ // evaluation of the controlling expression takes place before each
+ // execution of the loop body.
+ llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
+
+ // while(1) is common, avoid extra exit blocks. Be sure
+ // t
[PATCH] D86841: [clang] Adds noprogress attribute deduction for infinite loops
lebedev.ri added a comment. Does that wording apply to both the C and C++ (OpenCL?)? Regardless, might be good to test that. Comment at: clang/test/CodeGen/attr-noprogress.c:1-2 +// RUN: %clang_cc1 -S -emit-llvm %s -o - | grep " noprogress " | count 1 +// RUN: %clang_cc1 -S -emit-llvm %s -o - | grep llvm.loop.noprogress | count 1 + Please just FileCheck the expected output. Bonus points for using `llvm/utils/update_cc_test_checks.py` Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D86841/new/ https://reviews.llvm.org/D86841 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[PATCH] D86841: [clang] Adds noprogress attribute deduction for infinite loops
atmnpatel created this revision.
atmnpatel added reviewers: jdoerfert, aqjune, RalfJung.
Herald added subscribers: cfe-commits, danielkiss.
Herald added a project: clang.
atmnpatel requested review of this revision.
The `noprogress` LLVM IR attribute currently under discussion is deduced for
functions that contain loops that have a constant non-zero conditional as per
the C Spec. In addition, these particular loops have an additional bit of
metadata `llvm.loop.noprogress` so llvm can differentiate between the loops
that can be optimized out and ones that can't be optimized out. The changes to
the LoopDeletion pass is incoming.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D86841
Files:
clang/lib/CodeGen/CGLoopInfo.cpp
clang/lib/CodeGen/CGLoopInfo.h
clang/lib/CodeGen/CGStmt.cpp
clang/test/CodeGen/attr-noprogress.c
Index: clang/test/CodeGen/attr-noprogress.c
===
--- /dev/null
+++ clang/test/CodeGen/attr-noprogress.c
@@ -0,0 +1,18 @@
+// RUN: %clang_cc1 -S -emit-llvm %s -o - | grep " noprogress " | count 1
+// RUN: %clang_cc1 -S -emit-llvm %s -o - | grep llvm.loop.noprogress | count 1
+
+void f() {
+ for (; 1;) {
+ }
+}
+
+void w() {
+ while (1) {
+ }
+}
+
+void d() {
+ do {
+
+ } while (1);
+}
Index: clang/lib/CodeGen/CGStmt.cpp
===
--- clang/lib/CodeGen/CGStmt.cpp
+++ clang/lib/CodeGen/CGStmt.cpp
@@ -736,10 +736,26 @@
JumpDest LoopHeader = getJumpDestInCurrentScope("while.cond");
EmitBlock(LoopHeader.getBlock());
+ // Evaluate the conditional in the while header. C99 6.8.5.1: The
+ // evaluation of the controlling expression takes place before each
+ // execution of the loop body.
+ llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
+
+ // while(1) is common, avoid extra exit blocks. Be sure
+ // to correctly handle break/continue though.
+ bool EmitBoolCondBranch = true;
+ bool NoProgress = false;
+ if (llvm::ConstantInt *C = dyn_cast(BoolCondVal))
+if (C->isOne()) {
+ EmitBoolCondBranch = false;
+ CurFn->addFnAttr(llvm::Attribute::NoProgress);
+ NoProgress = true;
+}
+
const SourceRange &R = S.getSourceRange();
LoopStack.push(LoopHeader.getBlock(), CGM.getContext(), CGM.getCodeGenOpts(),
WhileAttrs, SourceLocToDebugLoc(R.getBegin()),
- SourceLocToDebugLoc(R.getEnd()));
+ SourceLocToDebugLoc(R.getEnd()), NoProgress);
// Create an exit block for when the condition fails, which will
// also become the break target.
@@ -760,18 +776,6 @@
if (S.getConditionVariable())
EmitDecl(*S.getConditionVariable());
- // Evaluate the conditional in the while header. C99 6.8.5.1: The
- // evaluation of the controlling expression takes place before each
- // execution of the loop body.
- llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
-
- // while(1) is common, avoid extra exit blocks. Be sure
- // to correctly handle break/continue though.
- bool EmitBoolCondBranch = true;
- if (llvm::ConstantInt *C = dyn_cast(BoolCondVal))
-if (C->isOne())
- EmitBoolCondBranch = false;
-
// As long as the condition is true, go to the loop body.
llvm::BasicBlock *LoopBody = createBasicBlock("while.body");
if (EmitBoolCondBranch) {
@@ -838,27 +842,33 @@
EmitBlock(LoopCond.getBlock());
- const SourceRange &R = S.getSourceRange();
- LoopStack.push(LoopBody, CGM.getContext(), CGM.getCodeGenOpts(), DoAttrs,
- SourceLocToDebugLoc(R.getBegin()),
- SourceLocToDebugLoc(R.getEnd()));
-
- // C99 6.8.5.2: "The evaluation of the controlling expression takes place
- // after each execution of the loop body."
-
// Evaluate the conditional in the while header.
// C99 6.8.5p2/p4: The first substatement is executed if the expression
// compares unequal to 0. The condition must be a scalar type.
llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
- BreakContinueStack.pop_back();
-
// "do {} while (0)" is common in macros, avoid extra blocks. Be sure
// to correctly handle break/continue though.
bool EmitBoolCondBranch = true;
- if (llvm::ConstantInt *C = dyn_cast(BoolCondVal))
+ bool NoProgress = false;
+ if (llvm::ConstantInt *C = dyn_cast(BoolCondVal)) {
if (C->isZero())
EmitBoolCondBranch = false;
+if (C->isOne()) {
+ CurFn->addFnAttr(llvm::Attribute::NoProgress);
+ NoProgress = true;
+}
+ }
+
+ const SourceRange &R = S.getSourceRange();
+ LoopStack.push(LoopBody, CGM.getContext(), CGM.getCodeGenOpts(), DoAttrs,
+ SourceLocToDebugLoc(R.getBegin()),
+ SourceLocToDebugLoc(R.getEnd()), NoProgress);
+
+ // C99 6.8.5.2: "The evaluation of the controlling expression takes place
+ // after each execution of the loop body."
+
+ BreakContinueStack.pop_back();
// As long as the condition
