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| author | Jeffrey A Law <law@cygnus.com> | 1999-08-31 06:28:16 +0000 |
|---|---|---|
| committer | Jeff Law <law@gcc.gnu.org> | 1999-08-31 00:28:16 -0600 |
| commit | 835126657b0fcfa7515b819c156751dfc10c9d5a (patch) | |
| tree | efe6a39dde5dee4ab7324404a9bb42925b184498 /gcc/emit-rtl.c | |
| parent | f425a8879b121e9145d9ce6a614cad1fc41bd50e (diff) | |
| download | gcc-835126657b0fcfa7515b819c156751dfc10c9d5a.zip gcc-835126657b0fcfa7515b819c156751dfc10c9d5a.tar.gz gcc-835126657b0fcfa7515b819c156751dfc10c9d5a.tar.bz2 | |
emit-rtl.c (copy_rtx_if_shared): A MEM which references virtual_stack_vars_rtx or virtual_incoming_args_rtx can...
* emit-rtl.c (copy_rtx_if_shared): A MEM which references
virtual_stack_vars_rtx or virtual_incoming_args_rtx can not
be shared.
From-SVN: r29001
Diffstat (limited to 'gcc/emit-rtl.c')
| -rw-r--r-- | gcc/emit-rtl.c | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/gcc/emit-rtl.c b/gcc/emit-rtl.c index b028556..79c179c 100644 --- a/gcc/emit-rtl.c +++ b/gcc/emit-rtl.c @@ -1678,16 +1678,18 @@ copy_rtx_if_shared (orig) return x; case MEM: - /* A MEM is allowed to be shared if its address is constant - or is a constant plus one of the special registers. */ - if (CONSTANT_ADDRESS_P (XEXP (x, 0)) - || XEXP (x, 0) == virtual_stack_vars_rtx - || XEXP (x, 0) == virtual_incoming_args_rtx) + /* A MEM is allowed to be shared if its address is constant. + + We used to allow sharing of MEMs which referenced + virtual_stack_vars_rtx or virtual_incoming_args_rtx, but + that can lose. instantiate_virtual_regs will not unshare + the MEMs, and combine may change the structure of the address + because it looks safe and profitable in one context, but + in some other context it creates unrecognizable RTL. */ + if (CONSTANT_ADDRESS_P (XEXP (x, 0))) return x; if (GET_CODE (XEXP (x, 0)) == PLUS - && (XEXP (XEXP (x, 0), 0) == virtual_stack_vars_rtx - || XEXP (XEXP (x, 0), 0) == virtual_incoming_args_rtx) && CONSTANT_ADDRESS_P (XEXP (XEXP (x, 0), 1))) { /* This MEM can appear in more than one place, |