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prevent extraneous nop past sibling call on sparc


Hello,

The sparc back-end emits an extra nop past calls at the very end of a
function, to prevent the return address from falling within a different
function, which causes trouble to some backtrace computation engines.

Such a nop is pointless for a sibling call since the return address is
setup explicitly, and this patch is a suggestion to remove it for this
particular case. We found this useful in the course of the development
of a machine code coverage analyzer.

OK ?

Thanks in advance,

Olivier

2010-08-19  Olivier Hainque  <hainque@adacore.com>

	* config/sparc/sparc.c (sparc_asm_function_epilogue): Don't output
	an extra nop past a sibling call at the very end.

	testsuite/
	* gcc.target/sparc/sibcall-dslot.c: New testcase.

Attachment: sibnop.dif
Description: Text document


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