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[PATCH i386] Allow sibcalls in no-PLT PIC
- From: Alexander Monakov <amonakov at ispras dot ru>
- To: gcc-patches at gcc dot gnu dot org
- Cc: Alexander Monakov <amonakov at ispras dot ru>, Rich Felker <dalias at libc dot org>
- Date: Mon, 4 May 2015 19:37:57 +0300
- Subject: [PATCH i386] Allow sibcalls in no-PLT PIC
- Authentication-results: sourceware.org; auth=none
- References: <1430757479-14241-1-git-send-email-amonakov at ispras dot ru>
With -fno-plt, we don't have to reject even direct calls as sibcall
This patch depends on '-fplt' flag that is introduced in another patch.
This patch requires that with -fno-plt all sibcall candidates go through
prepare_call_address that transforms the call to a GOT lookup.
* config/i386/i386.c (ix86_function_ok_for_sibcall): Check flag_plt.
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index f29e053..b734350 100644
@@ -5448,12 +5448,13 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
/* If we are generating position-independent code, we cannot sibcall
optimize any indirect call, or a direct call to a global function,
as the PLT requires %ebx be live. (Darwin does not have a PLT.) */
+ && flag_plt
&& (decl && !targetm.binds_local_p (decl)))
/* If we need to align the outgoing stack, then sibcalling would
unalign the stack, which may break the called function. */
if (ix86_minimum_incoming_stack_boundary (true)