Re: [PATCH v8 4/8] ppc64 ftrace_with_regs configuration variables

From: Torsten Duwe
Date: Mon Feb 15 2016 - 17:21:19 EST


On Mon, Feb 15, 2016 at 03:04:08PM +0100, Torsten Duwe wrote:
> If you use "-pg -mprofile-kernel", gcc seems to forget that, and omits the TOC
> load, for a similar assembler calling sequence.
>
> Looking at the code I can _understand_ why this is so, but my GCC knowledge
> is not that deep that I could easily _fix_ this reliably.

Nonetheless, here's a proposal.

--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -25154,6 +25154,10 @@ rs6000_emit_prologue (void)
{
cfun->machine->r2_setup_needed = df_regs_ever_live_p (TOC_REGNUM);

+ /* Profiling _will_ generate a call to a global _mcount. */
+ if (crtl->profile)
+ cfun->machine->r2_setup_needed = true;
+
/* With -mminimal-toc we may generate an extra use of r2 below. */
if (TARGET_TOC && TARGET_MINIMAL_TOC && get_pool_size () != 0)
cfun->machine->r2_setup_needed = true;