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| author | Bernd Edlinger <bernd.edlinger@hotmail.de> | 2016-06-06 12:31:59 +0000 |
|---|---|---|
| committer | Bernd Edlinger <edlinger@gcc.gnu.org> | 2016-06-06 12:31:59 +0000 |
| commit | 93671519e202e3bc5ab592bb6318aa738e4ae58f (patch) | |
| tree | 4c408260aa6953423d714fd94976bb8529014f19 /gcc/doc/extend.texi | |
| parent | 690f24b7754826f08fc19119dd3a30a6c07e9919 (diff) | |
| download | gcc-93671519e202e3bc5ab592bb6318aa738e4ae58f.zip gcc-93671519e202e3bc5ab592bb6318aa738e4ae58f.tar.gz gcc-93671519e202e3bc5ab592bb6318aa738e4ae58f.tar.bz2 | |
re PR c/24414 (Old-style asms don't clobber memory)
gcc/
2016-06-06 Bernd Edlinger <bernd.edlinger@hotmail.de>
PR c/24414
* cfgexpand.c (expand_asm_loc): Remove handling for ADDR_EXPR.
Implicitly clobber memory for basic asm with non-empty assembler
string. Use targetm.md_asm_adjust also here.
* compare-elim.c (arithmetic_flags_clobber_p): Use asm_noperands here.
* final.c (final_scan_insn): Handle basic asm in PARALLEL block.
* gimple.c (gimple_asm_clobbers_memory_p): Handle basic asm with
non-empty assembler string.
* ira.c (compute_regs_asm_clobbered): Use asm_noperands here.
* recog.c (asm_noperands): Handle basic asm in PARALLEL block.
(decode_asm_operands): Handle basic asm in PARALLEL block.
(extract_insn): Handle basic asm in PARALLEL block.
* doc/extend.texi: Mention new behavior of basic asm.
* config/ia64/ia64 (rtx_needs_barrier): Handle ASM_INPUT here.
* config/pa/pa.c (branch_to_delay_slot_p, branch_needs_nop_p,
branch_needs_nop_p): Use asm_noperands.
gcc/testsuite/
2016-06-06 Bernd Edlinger <bernd.edlinger@hotmail.de>
PR c/24414
* gcc.target/i386/pr24414.c: New test.
From-SVN: r237133
Diffstat (limited to 'gcc/doc/extend.texi')
| -rw-r--r-- | gcc/doc/extend.texi | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index c85e6db..7208f33 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -7581,7 +7581,7 @@ means there is no way to communicate to the compiler what is happening inside them. GCC has no visibility of symbols in the @code{asm} and may discard them as unreferenced. It also does not know about side effects of the assembler code, such as modifications to memory or registers. Unlike -some compilers, GCC assumes that no changes to either memory or registers +some compilers, GCC assumes that no changes to general purpose registers occur. This assumption may change in a future release. To avoid complications from future changes to the semantics and the @@ -7605,6 +7605,10 @@ all basic @code{asm} blocks use the assembler dialect specified by the Basic @code{asm} provides no mechanism to provide different assembler strings for different dialects. +For basic @code{asm} with non-empty assembler string GCC assumes +the assembler block does not change any general purpose registers, +but it may read or write any globally accessible variable. + Here is an example of basic @code{asm} for i386: @example |