diff options
| -rw-r--r-- | ghc/includes/TailCalls.h | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/ghc/includes/TailCalls.h b/ghc/includes/TailCalls.h index 670da9546f..53db254b66 100644 --- a/ghc/includes/TailCalls.h +++ b/ghc/includes/TailCalls.h @@ -249,6 +249,8 @@ but uses $$dyncall if necessary to cope, just in case you aren't. function and these markers is shredded by the mangler. -------------------------------------------------------------------------- */ +#ifndef FB_ +#if __GNUC__ < 3 /* The following __DISCARD__() has become necessary with gcc 2.96 on x86. * It prevents gcc from moving stack manipulation code from the function * body (aka the Real Code) into the function prologue, ie, from moving it @@ -258,9 +260,17 @@ but uses $$dyncall if necessary to cope, just in case you aren't. * it just doesn't choose to do it at the moment. * -= chak */ - -#ifndef FB_ #define FB_ __asm__ volatile ("--- BEGIN ---"); __DISCARD__ (); +#else +/* The __DISCARD__() doesn't appear to be necessary with gcc >= 3.2 at + * least, and it does cause some difficulty, preventing gcc from + * optimising around the beginning of the function. In particular, + * gcc leaves some stack assignments in the prologue when the call is + * present. --SDM + + */ +#define FB_ __asm__ volatile ("--- BEGIN ---"); +#endif #endif #ifndef FE_ |