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| author | Jeffrey A Law <law@cygnus.com> | 1999-10-27 06:18:11 +0000 |
|---|---|---|
| committer | Jeff Law <law@gcc.gnu.org> | 1999-10-27 00:18:11 -0600 |
| commit | b3b5ad95e64d1d5ce7070924123d8727b9a86ba5 (patch) | |
| tree | d4f608001d1f7b6c042ca422febbfb232adb8d6b /gcc/alias.c | |
| parent | c831fdea4be7d36270bfd160bd818250e5f4f7d6 (diff) | |
| download | gcc-b3b5ad95e64d1d5ce7070924123d8727b9a86ba5.zip gcc-b3b5ad95e64d1d5ce7070924123d8727b9a86ba5.tar.gz gcc-b3b5ad95e64d1d5ce7070924123d8727b9a86ba5.tar.bz2 | |
alias.c: Update comments for ADDRESS.
* alias.c: Update comments for ADDRESS.
(nonlocal_reference_p): Look inside the ADDRESS to determine if
it is a local memory reference.
From-SVN: r30210
Diffstat (limited to 'gcc/alias.c')
| -rw-r--r-- | gcc/alias.c | 31 |
1 files changed, 23 insertions, 8 deletions
diff --git a/gcc/alias.c b/gcc/alias.c index cc50c1b..59578d7 100644 --- a/gcc/alias.c +++ b/gcc/alias.c @@ -121,12 +121,16 @@ static int nonlocal_reference_p PROTO((rtx)); A base address can be an ADDRESS, SYMBOL_REF, or LABEL_REF. ADDRESS expressions represent certain special values: function arguments and - the stack, frame, and argument pointers. The contents of an address - expression are not used (but they are descriptive for debugging); - only the address and mode matter. Pointer equality, not rtx_equal_p, - determines whether two ADDRESS expressions refer to the same base - address. The mode determines whether it is a function argument or - other special value. */ + the stack, frame, and argument pointers. + + The contents of an ADDRESS is not normally used, the mode of the + ADDRESS determines whether the ADDRESS is a function argument or some + other special value. Pointer equality, not rtx_equal_p, determines whether + two ADDRESS expressions refer to the same base address. + + The only use of the contents of an ADDRESS is for determining if the + current function performs nonlocal memory memory references for the + purposes of marking the function as a constant function. */ static rtx *reg_base_value; static rtx *new_reg_base_value; @@ -1422,8 +1426,19 @@ nonlocal_reference_p (x) base = find_base_term (XEXP (x, 0)); if (base) { - /* Stack references are local. */ - if (GET_CODE (base) == ADDRESS && GET_MODE (base) == Pmode) + /* A Pmode ADDRESS could be a reference via the structure value + address or static chain. Such memory references are nonlocal. + + Thus, we have to examine the contents of the ADDRESS to find + out if this is a local reference or not. */ + if (GET_CODE (base) == ADDRESS + && GET_MODE (base) == Pmode + && (XEXP (base, 0) == stack_pointer_rtx + || XEXP (base, 0) == arg_pointer_rtx +#if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM + || XEXP (base, 0) == hard_frame_pointer_rtx +#endif + || XEXP (base, 0) == frame_pointer_rtx)) return 0; /* Constants in the function's constant pool are constant. */ if (GET_CODE (base) == SYMBOL_REF && CONSTANT_POOL_ADDRESS_P (base)) |