This revision was automatically updated to reflect the committed changes.
Closed by commit rL299951: Fix PR13910: Don't warn that __builtin_unreachable()
is unreachable (authored by arphaman).
Changed prior to commit:
https://reviews.llvm.org/D25321?vs=73898&id=94834#toc
Repository:
rL LLVM
https://reviews.llvm.org/D25321
Files:
cfe/trunk/lib/Analysis/ReachableCode.cpp
cfe/trunk/test/Sema/warn-unreachable.c
Index: cfe/trunk/test/Sema/warn-unreachable.c
===================================================================
--- cfe/trunk/test/Sema/warn-unreachable.c
+++ cfe/trunk/test/Sema/warn-unreachable.c
@@ -461,3 +461,40 @@
if (!true) // expected-note {{silence by adding parentheses to mark code as
explicitly dead}}
testTrueFalseMacros(); // expected-warning {{code will never be executed}}
}
+
+int pr13910_foo(int x) {
+ if (x == 1)
+ return 0;
+ else
+ return x;
+ __builtin_unreachable(); // expected no warning
+}
+
+int pr13910_bar(int x) {
+ switch (x) {
+ default:
+ return x + 1;
+ }
+ pr13910_foo(x); // expected-warning {{code will never be executed}}
+}
+
+int pr13910_bar2(int x) {
+ if (x == 1)
+ return 0;
+ else
+ return x;
+ pr13910_foo(x); // expected-warning {{code will never be executed}}
+ __builtin_unreachable(); // expected no warning
+ pr13910_foo(x); // expected-warning {{code will never be executed}}
+}
+
+void pr13910_noreturn() {
+ raze();
+ __builtin_unreachable(); // expected no warning
+}
+
+void pr13910_assert() {
+ myassert(0 && "unreachable");
+ return;
+ __builtin_unreachable(); // expected no warning
+}
Index: cfe/trunk/lib/Analysis/ReachableCode.cpp
===================================================================
--- cfe/trunk/lib/Analysis/ReachableCode.cpp
+++ cfe/trunk/lib/Analysis/ReachableCode.cpp
@@ -58,6 +58,14 @@
return false;
}
+static bool isBuiltinUnreachable(const Stmt *S) {
+ if (const auto *DRE = dyn_cast<DeclRefExpr>(S))
+ if (const auto *FDecl = dyn_cast<FunctionDecl>(DRE->getDecl()))
+ return FDecl->getIdentifier() &&
+ FDecl->getBuiltinID() == Builtin::BI__builtin_unreachable;
+ return false;
+}
+
static bool isDeadReturn(const CFGBlock *B, const Stmt *S) {
// Look to see if the current control flow ends with a 'return', and see if
// 'S' is a substatement. The 'return' may not be the last element in the
@@ -592,8 +600,7 @@
if (isa<BreakStmt>(S)) {
UK = reachable_code::UK_Break;
- }
- else if (isTrivialDoWhile(B, S)) {
+ } else if (isTrivialDoWhile(B, S) || isBuiltinUnreachable(S)) {
return;
}
else if (isDeadReturn(B, S)) {
Index: cfe/trunk/test/Sema/warn-unreachable.c
===================================================================
--- cfe/trunk/test/Sema/warn-unreachable.c
+++ cfe/trunk/test/Sema/warn-unreachable.c
@@ -461,3 +461,40 @@
if (!true) // expected-note {{silence by adding parentheses to mark code as explicitly dead}}
testTrueFalseMacros(); // expected-warning {{code will never be executed}}
}
+
+int pr13910_foo(int x) {
+ if (x == 1)
+ return 0;
+ else
+ return x;
+ __builtin_unreachable(); // expected no warning
+}
+
+int pr13910_bar(int x) {
+ switch (x) {
+ default:
+ return x + 1;
+ }
+ pr13910_foo(x); // expected-warning {{code will never be executed}}
+}
+
+int pr13910_bar2(int x) {
+ if (x == 1)
+ return 0;
+ else
+ return x;
+ pr13910_foo(x); // expected-warning {{code will never be executed}}
+ __builtin_unreachable(); // expected no warning
+ pr13910_foo(x); // expected-warning {{code will never be executed}}
+}
+
+void pr13910_noreturn() {
+ raze();
+ __builtin_unreachable(); // expected no warning
+}
+
+void pr13910_assert() {
+ myassert(0 && "unreachable");
+ return;
+ __builtin_unreachable(); // expected no warning
+}
Index: cfe/trunk/lib/Analysis/ReachableCode.cpp
===================================================================
--- cfe/trunk/lib/Analysis/ReachableCode.cpp
+++ cfe/trunk/lib/Analysis/ReachableCode.cpp
@@ -58,6 +58,14 @@
return false;
}
+static bool isBuiltinUnreachable(const Stmt *S) {
+ if (const auto *DRE = dyn_cast<DeclRefExpr>(S))
+ if (const auto *FDecl = dyn_cast<FunctionDecl>(DRE->getDecl()))
+ return FDecl->getIdentifier() &&
+ FDecl->getBuiltinID() == Builtin::BI__builtin_unreachable;
+ return false;
+}
+
static bool isDeadReturn(const CFGBlock *B, const Stmt *S) {
// Look to see if the current control flow ends with a 'return', and see if
// 'S' is a substatement. The 'return' may not be the last element in the
@@ -592,8 +600,7 @@
if (isa<BreakStmt>(S)) {
UK = reachable_code::UK_Break;
- }
- else if (isTrivialDoWhile(B, S)) {
+ } else if (isTrivialDoWhile(B, S) || isBuiltinUnreachable(S)) {
return;
}
else if (isDeadReturn(B, S)) {
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