On Wed, Jul 20, 2011 at 9:46 PM, Uros Bizjak <ubiz...@gmail.com> wrote:
>> Note that SUBREG_PROMOTED_UNSIGNED_P wasn't designed for paradoxical subregs,
>> but for regular subregs (typically of word-sized objects). You should check
>> that the ones created for x32 (because of POINTERS_EXTEND_UNSIGNED I guess)
>> are legitimate.
I have left out paradoxical subreg stuff ATM and committed following
patch that allows subregs of multi-word values in addresses.
2011-07-20 Uros Bizjak <ubiz...@gmail.com>
* config/i386/i386.c (ix86_decompose_address): Allow only subregs
of DImode hard registers in index.
(ix86_legitimate_address_p): Allow subregs of base and index to span
more than a word. Assert that subregs of base and index satisfy
register_no_elim_operand predicates. Reject addresses where
base and index have different modes.
Patch was bootstrapped and regression tested on x86_64-pc-linux-gnu
{,-m32} and committed to mainline SVN.
(I will prepare a followup [RFC] patch that also allows paradoxical
(?) subregs for experimenting and testing on x32 target).
Uros.
Index: i386.c
===================================================================
--- i386.c (revision 176533)
+++ i386.c (working copy)
@@ -11197,6 +11197,16 @@ ix86_decompose_address (rtx addr, struct
else
disp = addr; /* displacement */
+ if (index)
+ {
+ if (REG_P (index))
+ ;
+ /* Allow only subregs of DImode hard regs. */
+ else if (GET_CODE (index) == SUBREG
+ && !register_no_elim_operand (SUBREG_REG (index), DImode))
+ return 0;
+ }
+
/* Extract the integral value of scale. */
if (scale_rtx)
{
@@ -11630,23 +11640,18 @@ ix86_legitimate_address_p (enum machine_
disp = parts.disp;
scale = parts.scale;
- /* Validate base register.
-
- Don't allow SUBREG's that span more than a word here. It can lead to
spill
- failures when the base is one word out of a two word structure, which is
- represented internally as a DImode int. */
-
+ /* Validate base register. */
if (base)
{
rtx reg;
if (REG_P (base))
reg = base;
- else if (GET_CODE (base) == SUBREG
- && REG_P (SUBREG_REG (base))
- && GET_MODE_SIZE (GET_MODE (SUBREG_REG (base)))
- <= UNITS_PER_WORD)
- reg = SUBREG_REG (base);
+ else if (GET_CODE (base) == SUBREG && REG_P (SUBREG_REG (base)))
+ {
+ reg = SUBREG_REG (base);
+ gcc_assert (register_no_elim_operand (reg, DImode));
+ }
else
/* Base is not a register. */
return false;
@@ -11660,21 +11665,18 @@ ix86_legitimate_address_p (enum machine_
return false;
}
- /* Validate index register.
-
- Don't allow SUBREG's that span more than a word here -- same as above. */
-
+ /* Validate index register. */
if (index)
{
rtx reg;
if (REG_P (index))
reg = index;
- else if (GET_CODE (index) == SUBREG
- && REG_P (SUBREG_REG (index))
- && GET_MODE_SIZE (GET_MODE (SUBREG_REG (index)))
- <= UNITS_PER_WORD)
- reg = SUBREG_REG (index);
+ else if (GET_CODE (index) == SUBREG && REG_P (SUBREG_REG (index)))
+ {
+ reg = SUBREG_REG (index);
+ gcc_assert (register_no_elim_operand (reg, DImode));
+ }
else
/* Index is not a register. */
return false;
@@ -11688,6 +11690,11 @@ ix86_legitimate_address_p (enum machine_
return false;
}
+ /* Index and base should have the same mode. */
+ if (base && index
+ && GET_MODE (base) != GET_MODE (index))
+ return false;
+
/* Validate scale factor. */
if (scale != 1)
{
