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re PR rtl-optimization/9771 ([x86] wrong ebp optimisation)

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PR rtl-optimization/9771
	* regclass.c (CALL_REALLY_USED_REGNO_P): New macro to eliminate
	conditional compilation in init_reg_sets_1.
	(init_reg_sets_1): Let global_regs[i] take priority over the frame
	(but not stack) pointer exceptions to regs_invalidated_by_call.
	(globalize_reg): Globalizing a fixed register may need to update
	regs_invalidated_by_call.

	* gcc.dg/pr9771-1.c: New test case.

From-SVN: r87516
This commit is contained in:
Roger Sayle 2004-09-14 22:52:41 +00:00 committed by Roger Sayle
parent 1810f6edaa
commit f6ae6c51df
4 changed files with 77 additions and 9 deletions
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10
gcc/ChangeLog
View File

@ -1,3 +1,13 @@
2004-09-14 Roger Sayle <roger@eyesopen.com>
PR rtl-optimization/9771
* regclass.c (CALL_REALLY_USED_REGNO_P): New macro to eliminate
conditional compilation in init_reg_sets_1.
(init_reg_sets_1): Let global_regs[i] take priority over the frame
(but not stack) pointer exceptions to regs_invalidated_by_call.
(globalize_reg): Globalizing a fixed register may need to update
regs_invalidated_by_call.
2004-09-14 Diego Novillo <dnovillo@redhat.com>
PR tree-optimization/15262

28
gcc/regclass.c
View File

@ -104,6 +104,13 @@ static const char initial_call_used_regs[] = CALL_USED_REGISTERS;
char call_really_used_regs[] = CALL_REALLY_USED_REGISTERS;
#endif
#ifdef CALL_REALLY_USED_REGISTERS
#define CALL_REALLY_USED_REGNO_P(X) call_really_used_regs[X]
#else
#define CALL_REALLY_USED_REGNO_P(X) call_used_regs[X]
#endif
/* Indexed by hard register number, contains 1 for registers that are
fixed use or call used registers that cannot hold quantities across
calls even if we are willing to save and restore them. call fixed
@ -454,7 +461,11 @@ init_reg_sets_1 (void)
If we are generating PIC code, the PIC offset table register is
preserved across calls, though the target can override that. */
if (i == STACK_POINTER_REGNUM || i == FRAME_POINTER_REGNUM)
if (i == STACK_POINTER_REGNUM)
;
else if (global_regs[i])
SET_HARD_REG_BIT (regs_invalidated_by_call, i);
else if (i == FRAME_POINTER_REGNUM)
;
#if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
else if (i == HARD_FRAME_POINTER_REGNUM)
@ -468,13 +479,7 @@ init_reg_sets_1 (void)
else if (i == (unsigned) PIC_OFFSET_TABLE_REGNUM && fixed_regs[i])
;
#endif
else if (0
#ifdef CALL_REALLY_USED_REGISTERS
|| call_really_used_regs[i]
#else
|| call_used_regs[i]
#endif
|| global_regs[i])
else if (CALL_REALLY_USED_REGNO_P (i))
SET_HARD_REG_BIT (regs_invalidated_by_call, i);
}
@ -800,6 +805,12 @@ globalize_reg (int i)
global_regs[i] = 1;
/* If we're globalizing the frame pointer, we need to set the
appropriate regs_invalidated_by_call bit, even if it's already
set in fixed_regs. */
if (i != STACK_POINTER_REGNUM)
SET_HARD_REG_BIT (regs_invalidated_by_call, i);
/* If already fixed, nothing else to do. */
if (fixed_regs[i])
return;
@ -813,7 +824,6 @@ globalize_reg (int i)
SET_HARD_REG_BIT (fixed_reg_set, i);
SET_HARD_REG_BIT (call_used_reg_set, i);
SET_HARD_REG_BIT (call_fixed_reg_set, i);
SET_HARD_REG_BIT (regs_invalidated_by_call, i);
}
/* Now the data and code for the `regclass' pass, which happens

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2004-09-14 Roger Sayle <roger@eyesopen.com>
PR rtl-optimization/9771
* gcc.dg/pr9771-1.c: New test case.
2004-09-14 Diego Novillo <dnovillo@redhat.com>
PR tree-optimization/15262

43
gcc/testsuite/gcc.dg/pr9771-1.c Normal file
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@ -0,0 +1,43 @@
/* PR rtl-optimization/9771 */
/* { dg-do run { target i?86-*-* } } */
/* { dg-options "-O2 -fomit-frame-pointer -ffixed-ebp" } */
extern void abort(void);
extern void exit(int);
register long *B asm ("ebp");
long x = 10;
long y = 20;
void bar(void)
{
B = &y;
}
void foo()
{
long *adr = B;
long save = *adr;
*adr = 123;
bar();
*adr = save;
}
int main()
{
B = &x;
foo();
if (x != 10 || y != 20)
abort();
/* We can't return, as our caller may assume %ebp is preserved! */
/* We could save/restore it (like foo), but its easier to exit. */
exit(0);
}