On Thu, May 11, 2017 at 8:28 PM, Jeff Law <[email protected]> wrote:
>> Attached patch changes compare-elim.c order to what i386.md expects.
>>
>> Thoughts?
>
> Haven't looked at the patch itself. But I do have the necessary bits to
> convert the mn103 port. It was slightly more than just fixing the md file,
> but nothing significant or time consuming. The net result is 100% identical
> code for newlib before your patch vs after your patch w/mn103 converted.
>
> Hell, it was easy enough, I'll take a cut at the rx port.
Attached to this message, please find a version of the patch that
should ease transition of other targets by declaring and handling a
temporary macro. This way, aarch64 can also test what happens when
postreload cmp elimination goes live for real.
2017-05-11 Uros Bizjak <[email protected]>
* compare-elim.c (try_eliminate_compare)
[TARGET_HAS_ALTERNATIVE_POSTRELOAD_EMBEDDED_COMPARE_PATTERNS]:
Canonicalize operation with embedded compare to
[(set (reg:CCM) (compare:CCM (operation) (immediate)))
(set (reg) (operation)].
* config/i386/i386.c (TARGET_FLAGS_REGNUM): New define.
* config/i386/i386.h
(TARGET_HAS_ALTERNATIVE_POSTRELOAD_EMBEDDED_COMPARE_PATTERNS): Ditto.
Uros.
Index: compare-elim.c
===================================================================
--- compare-elim.c (revision 247914)
+++ compare-elim.c (working copy)
@@ -45,9 +45,9 @@ along with GCC; see the file COPYING3. If not see
(3) If an insn of form (2) can usefully set the flags, there is
another pattern of the form
- [(set (reg) (operation)
- (set (reg:CCM) (compare:CCM (operation) (immediate)))]
-
+ [(set (reg:CCM) (compare:CCM (operation) (immediate)))
+ (set (reg) (operation)]
+
The mode CCM will be chosen as if by SELECT_CC_MODE.
Note that unlike NOTICE_UPDATE_CC, we do not handle memory operands.
@@ -582,7 +582,7 @@ equivalent_reg_at_start (rtx reg, rtx_insn *end, r
static bool
try_eliminate_compare (struct comparison *cmp)
{
- rtx x, flags, in_a, in_b, cmp_src;
+ rtx flags, in_a, in_b, cmp_src;
/* We must have found an interesting "clobber" preceding the compare. */
if (cmp->prev_clobber == NULL)
@@ -628,7 +628,8 @@ try_eliminate_compare (struct comparison *cmp)
Validate that PREV_CLOBBER itself does in fact refer to IN_A. Do
recall that we've already validated the shape of PREV_CLOBBER. */
rtx_insn *insn = cmp->prev_clobber;
- x = XVECEXP (PATTERN (insn), 0, 0);
+
+ rtx x = XVECEXP (PATTERN (insn), 0, 0);
if (rtx_equal_p (SET_DEST (x), in_a))
cmp_src = SET_SRC (x);
@@ -666,13 +667,28 @@ try_eliminate_compare (struct comparison *cmp)
flags = gen_rtx_REG (cmp->orig_mode, targetm.flags_regnum);
/* Generate a new comparison for installation in the setter. */
- x = copy_rtx (cmp_src);
- x = gen_rtx_COMPARE (GET_MODE (flags), x, in_b);
- x = gen_rtx_SET (flags, x);
+ rtx y = copy_rtx (cmp_src);
+ y = gen_rtx_COMPARE (GET_MODE (flags), y, in_b);
+ y = gen_rtx_SET (flags, y);
+#if TARGET_HAS_ALTERNATIVE_POSTRELOAD_EMBEDDED_COMPARE_PATTERNS
+ /* Canonicalize instruction to:
+ [(set (reg:CCM) (compare:CCM (operation) (immediate)))
+ (set (reg) (operation)] */
+
+ rtvec v = rtvec_alloc (2);
+ RTVEC_ELT (v, 0) = y;
+ RTVEC_ELT (v, 1) = x;
+
+ rtx pat = gen_rtx_PARALLEL (VOIDmode, v);
+
/* Succeed if the new instruction is valid. Note that we may have started
a change group within maybe_select_cc_mode, therefore we must continue. */
- validate_change (insn, &XVECEXP (PATTERN (insn), 0, 1), x, true);
+ validate_change (insn, &PATTERN (insn), pat, true);
+#else
+ validate_change (insn, &XVECEXP (PATTERN (insn), 0, 1), y, true);
+#endif
+
if (!apply_change_group ())
return false;
Index: config/i386/i386.c
===================================================================
--- config/i386/i386.c (revision 247914)
+++ config/i386/i386.c (working copy)
@@ -52043,6 +52043,8 @@ ix86_run_selftests (void)
#undef TARGET_ADDRESS_COST
#define TARGET_ADDRESS_COST ix86_address_cost
+#undef TARGET_FLAGS_REGNUM
+#define TARGET_FLAGS_REGNUM FLAGS_REG
#undef TARGET_FIXED_CONDITION_CODE_REGS
#define TARGET_FIXED_CONDITION_CODE_REGS ix86_fixed_condition_code_regs
#undef TARGET_CC_MODES_COMPATIBLE
Index: config/i386/i386.h
===================================================================
--- config/i386/i386.h (revision 247914)
+++ config/i386/i386.h (working copy)
@@ -2658,6 +2658,9 @@ extern void debug_dispatch_window (int);
#define TARGET_SUPPORTS_WIDE_INT 1
+/* Temporary macro to ease transition, should be removed ASAP. */
+#define TARGET_HAS_ALTERNATIVE_POSTRELOAD_EMBEDDED_COMPARE_PATTERNS 1
+
/*
Local variables:
version-control: t
