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[PR103097] tolerate reg-stack cross-block malformed asms

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The testcase shows malformed asms in one block confuse reg-stack logic
in another block.  Moving the resetting of any_malformed_asm to the
end of the pass enables it to take effect throughout the affected
function.


for  gcc/ChangeLog

	PR target/103097
	* reg-stack.c (convert_regs_1): Move any_malformed_asm
	resetting...
	(reg_to_stack): ... here.

for  gcc/testsuite/ChangeLog

	PR target/103097
	* gcc.target/i386/pr103097.c: New.
This commit is contained in:
Alexandre Oliva 2021-12-08 23:37:15 -03:00 • committed by Alexandre Oliva
parent 50e8b0c9bc
commit af93386ffc
2 changed files with 32 additions and 3 deletions
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5
gcc/reg-stack.c
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@ -453,7 +453,7 @@ get_true_reg (rtx *pat)
}
}
/* Set if we find any malformed asms in a block. */
/* Set if we find any malformed asms in a function. */
static bool any_malformed_asm;
/* There are many rules that an asm statement for stack-like regs must
@ -3014,8 +3014,6 @@ convert_regs_1 (basic_block block)
bool cfg_altered = false;
int debug_insns_with_starting_stack = 0;
any_malformed_asm = false;
/* Choose an initial stack layout, if one hasn't already been chosen. */
if (bi->stack_in.top == -2)
{
@ -3385,6 +3383,7 @@ reg_to_stack (void)
0, sizeof (char) * (max_uid + 1));
convert_regs ();
any_malformed_asm = false;
free_aux_for_blocks ();
return true;

30
gcc/testsuite/gcc.target/i386/pr103097.c Normal file
View file

@ -0,0 +1,30 @@
/* { dg-do compile } */
/* { dg-options "-O1 -fharden-conditional-branches" } */
/* This is a slightly simplified version of
gcc.target/s390/vector/long-double-asm-earlyclobber.c. On x86, the f
constraints in asm statements imposes some requirements that the testcase
doesn't meet. What's unusual is that -fharden-conditional-branches extends
the effects of the malformed asm onto a different basic blocks, which
reg-stack did not expect. */
#include <assert.h>
#include <stdint.h>
void
f (void)
{
long double res, x = 0;
asm("" : "=f"(res) /* { dg-error "must specify a single register" } */
: "0"(x));
assert (res == x);
}
void
g (void)
{
long double res, x = 0;
asm("" : "=g"(res) /* this is ok. */
: "0"(x));
assert (res == x);
}