https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101277
Bug ID: 101277
Summary: Assert in constructor generates code for statically
checkable expression
Product: gcc
Version: 10.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: p.waydan at gmail dot com
Target Milestone: ---
Created attachment 51092
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51092&action=edit
-v output for Compiler Explorer compilation
Given the following code segment compiled with C++14 and above:
#include <cassert>
struct Positive { constexpr Positive(int x) {assert(x >= 0);} };
int foo(Positive) {return 1;}
int main()
{
return foo(Positive{1});
}
GCC 10.1 and 10.2 will generate code to check if the assertion is true even
though it is statically checkable. This occurs for optimization levels -O0,
-Os, and -O2, but the assertion is elided for optimization levels -Og, -O1, and
-O3.
The assertion is always elided in GCC 9.4 and below as well as GCC 10.3 and
above.
Please see https://godbolt.org/z/3scPr1P7W for a comparison of x86-64 assembly
with different GCC versions.
