4d4d903767
in places such as constant folding
Previously some places that should have handled
__builtin_expect_with_probability is missing, so in some case it acts
differently than __builtin_expect.
For example it was not handled in constant folding, thus in the
following program, the "if" condition should be constantly true and
folded, but previously it was not handled and cause warning "control may
reach end of non-void function" (while __builtin_expect does not):
__attribute__((noreturn)) extern void bar();
int foo(int x, int y) {
if (y) {
if (__builtin_expect_with_probability(1, 1, 1))
bar();
}
else
return 0;
}
Now it's fixed.
Differential Revisions: https://reviews.llvm.org/D83362
59 lines
2.8 KiB
C++
59 lines
2.8 KiB
C++
// RUN: %clang_cc1 -fsyntax-only -verify %s
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__attribute__((noreturn)) extern void bar();
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int test_no_warn(int x) {
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if (x) {
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if (__builtin_expect_with_probability(1, 1, 1))
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bar();
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} else {
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return 0;
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}
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} // should not emit warn "control may reach end of non-void function" here since expr is constantly true, so the "if(__bui..)" should be constantly true condition and be ignored
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template <int b> void tempf() {
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static_assert(b == 1, "should be evaluated as 1"); // should not have error here
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}
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constexpr int constf() {
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return __builtin_expect_with_probability(1, 1, 1);
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}
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void foo() {
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tempf<__builtin_expect_with_probability(1, 1, 1)>();
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constexpr int f = constf();
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static_assert(f == 1, "should be evaluated as 1"); // should not have error here
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}
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extern int global;
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struct S {
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static constexpr float prob = 0.7;
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};
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template<typename T>
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void expect_taken(int x) {
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if (__builtin_expect_with_probability(x > 0, 1, T::prob)) {
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global++;
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}
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}
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void test(int x, double p) { // expected-note {{declared here}}
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bool dummy;
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dummy = __builtin_expect_with_probability(x > 0, 1, 0.9);
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dummy = __builtin_expect_with_probability(x > 0, 1, 1.1); // expected-error {{probability argument to __builtin_expect_with_probability is outside the range [0.0, 1.0]}}
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dummy = __builtin_expect_with_probability(x > 0, 1, -1); // expected-error {{probability argument to __builtin_expect_with_probability is outside the range [0.0, 1.0]}}
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dummy = __builtin_expect_with_probability(x > 0, 1, p); // expected-error {{probability argument to __builtin_expect_with_probability must be constant floating-point expression}} expected-note {{read of non-constexpr variable 'p' is not allowed in a constant expression}}
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dummy = __builtin_expect_with_probability(x > 0, 1, "aa"); // expected-error {{cannot initialize a parameter of type 'double' with an lvalue of type 'const char [3]'}}
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dummy = __builtin_expect_with_probability(x > 0, 1, __builtin_nan("")); // expected-error {{probability argument to __builtin_expect_with_probability is outside the range [0.0, 1.0]}}
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dummy = __builtin_expect_with_probability(x > 0, 1, __builtin_inf()); // expected-error {{probability argument to __builtin_expect_with_probability is outside the range [0.0, 1.0]}}
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dummy = __builtin_expect_with_probability(x > 0, 1, -0.0);
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dummy = __builtin_expect_with_probability(x > 0, 1, 1.0 + __DBL_EPSILON__); // expected-error {{probability argument to __builtin_expect_with_probability is outside the range [0.0, 1.0]}}
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dummy = __builtin_expect_with_probability(x > 0, 1, -__DBL_DENORM_MIN__); // expected-error {{probability argument to __builtin_expect_with_probability is outside the range [0.0, 1.0]}}
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constexpr double pd = 0.7;
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dummy = __builtin_expect_with_probability(x > 0, 1, pd);
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constexpr int pi = 1;
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dummy = __builtin_expect_with_probability(x > 0, 1, pi);
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expect_taken<S>(x);
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}
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