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| author | Uros Bizjak <ubizjak@gmail.com> | 2021-06-09 09:46:00 +0200 |
|---|---|---|
| committer | Uros Bizjak <ubizjak@gmail.com> | 2021-06-09 09:46:42 +0200 |
| commit | 267dbd42f42c52a515f49c0875d296a9cf5988fe (patch) | |
| tree | c01901d59c851d28d87b018b74aa9c8412920bfa /gcc | |
| parent | 59d6713a138edf60827189b27c6b4ce98069c196 (diff) | |
| download | gcc-267dbd42f42c52a515f49c0875d296a9cf5988fe.zip gcc-267dbd42f42c52a515f49c0875d296a9cf5988fe.tar.gz gcc-267dbd42f42c52a515f49c0875d296a9cf5988fe.tar.bz2 | |
i386: Do not emit segment overrides for %p and %P [PR100936]
Using %p to move the address of a symbol using LEA:
asm ("lea %p1, %0" : "=r"(addr) : "m"(var));
emits assembler warning when VAR is declared in a non-generic address space:
Warning: segment override on `lea' is ineffectual
The problem is with %p operand modifier, which should emit raw symbol name:
p -- print raw symbol name.
Similar problem exists with %P modifier, trying to CALL or JMP to an
overridden symbol,e.g:
call %gs:zzz
jmp %gs:zzz
emits assembler warning:
Warning: skipping prefixes on `call'
Warning: skipping prefixes on `jmp'
Ensure that %p and %P never emit segment overrides.
2021-06-08 Uroš Bizjak <ubizjak@gmail.com>
gcc/
PR target/100936
* config/i386/i386.c (print_operand_address_as): Rename "no_rip"
argument to "raw". Do not emit segment overrides when "raw" is true.
gcc/testsuite/
PR target/100936
* gcc.target/i386/pr100936.c: New test.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/config/i386/i386.c | 6 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.target/i386/pr100936.c | 34 |
2 files changed, 37 insertions, 3 deletions
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c index b0d19a6..05b8dc8 100644 --- a/gcc/config/i386/i386.c +++ b/gcc/config/i386/i386.c @@ -13531,7 +13531,7 @@ ix86_print_operand_punct_valid_p (unsigned char code) static void ix86_print_operand_address_as (FILE *file, rtx addr, - addr_space_t as, bool no_rip) + addr_space_t as, bool raw) { struct ix86_address parts; rtx base, index, disp; @@ -13570,7 +13570,7 @@ ix86_print_operand_address_as (FILE *file, rtx addr, else gcc_assert (ADDR_SPACE_GENERIC_P (parts.seg)); - if (!ADDR_SPACE_GENERIC_P (as)) + if (!ADDR_SPACE_GENERIC_P (as) && !raw) { if (ASSEMBLER_DIALECT == ASM_ATT) putc ('%', file); @@ -13589,7 +13589,7 @@ ix86_print_operand_address_as (FILE *file, rtx addr, } /* Use one byte shorter RIP relative addressing for 64bit mode. */ - if (TARGET_64BIT && !base && !index && !no_rip) + if (TARGET_64BIT && !base && !index && !raw) { rtx symbol = disp; diff --git a/gcc/testsuite/gcc.target/i386/pr100936.c b/gcc/testsuite/gcc.target/i386/pr100936.c new file mode 100644 index 0000000..c076cbb --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr100936.c @@ -0,0 +1,34 @@ +/* PR target/100936 */ +/* { dg-do assemble } */ +/* { dg-options "-O2" } */ + +__seg_gs int var; + +static int +*foo (void) +{ + int *addr; + + asm ("lea %p1, %0" : "=r"(addr) : "m"(var)); + + return addr; +} + +static int +bar (int *addr) +{ + int val; + + asm ("mov %%gs:%1, %0" : "=r"(val) : "m"(*addr)); + + return val; +} + +int +baz (void) +{ + int *addr = foo(); + int val = bar (addr); + + return val; +} |