https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67753
John David Anglin <danglin at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |aoliva at gcc dot gnu.org --- Comment #3 from John David Anglin <danglin at gcc dot gnu.org> --- I'm not 100% certain but I believe this regression was introduced in r228175. It can be seen in the attached assembler output from /test/gnu/gcc/objdir/gcc/xgcc -B/test/gnu/gcc/objdir/gcc/ /test/gnu/gcc/gcc/gcc/testsuite/gcc.c-torture/execute/pr38969.c -fno-diagnostics-show-caret -fdiagnostics-color=never -O1 -w -lm -o ./pr38969.exe -v -save-temps that the parameter handling assumes the original call value 'a' was passed on the stack. In fact, it is passed in registers as its size is less than or equal to 64 bits.