From 713cb52a7879014eb365d845d5bbc06b577dae07 Mon Sep 17 00:00:00 2001
From: sayle <sayle@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Mon, 6 Oct 2003 12:48:49 +0000
Subject: [PATCH] * optabs.c (prepare_float_lib_cmp): Attach a
REG_EQUAL note describing the return value of the comparison libcall
to the REG_RETVAL instruction of the emitted sequence.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@72148 138bc75d-0d04-0410-961f-82ee72b054a4
---
gcc/ChangeLog | 6 ++++
gcc/optabs.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++++--
2 files changed, 94 insertions(+), 2 deletions(-)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a0112d2ca75d..4b4130637bce 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2003-10-06 Roger Sayle <roger@eyesopen.com>
+
+ * optabs.c (prepare_float_lib_cmp): Attach a REG_EQUAL note
+ describing the return value of the comparison libcall to the
+ REG_RETVAL instruction of the emitted sequence.
+
2003-10-06 Eric Botcazou <ebotcazou@libertysurf.fr>
PR optimization/12215
diff --git a/gcc/optabs.c b/gcc/optabs.c
index bd9306d4df13..7f8affc0ddf7 100644
--- a/gcc/optabs.c
+++ b/gcc/optabs.c
@@ -3877,6 +3877,7 @@ prepare_float_lib_cmp (rtx *px, rtx *py, enum rtx_code *pcomparison,
rtx y = protect_from_queue (*py, 0);
enum machine_mode orig_mode = GET_MODE (x);
enum machine_mode mode;
+ rtx before_call;
rtx libfunc = 0;
rtx result;
@@ -3903,12 +3904,97 @@ prepare_float_lib_cmp (rtx *px, rtx *py, enum rtx_code *pcomparison,
y = convert_to_mode (mode, y, 0);
}
+ before_call = get_last_insn ();
+
+ result = emit_library_call_value (libfunc, NULL_RTX, LCT_CONST_MAKE_BLOCK,
+ word_mode, 2, x, mode, y, mode);
+
+ /* If we're optimizing attach a REG_EQUAL note describing the semantics
+ of the libcall to the RTL. The allows the RTL optimizers to delete
+ the libcall if the condition can be determined at compile-time. */
+ if (optimize
+ && ! side_effects_p (x)
+ && ! side_effects_p (y))
+ {
+ /* Search backwards through the insns emitted above looking for
+ the instruction with the REG_RETVAL note. */
+ rtx last = get_last_insn ();
+ while (last != before_call)
+ {
+ if (find_reg_note (last, REG_RETVAL, NULL))
+ break;
+ last = PREV_INSN (last);
+ }
+
+ if (last != before_call)
+ {
+ rtx equiv;
+ if (comparison == UNORDERED)
+ {
+ rtx temp = simplify_gen_relational (NE, word_mode,
+ mode, x, x);
+ equiv = simplify_gen_relational (NE, word_mode,
+ mode, y, y);
+ equiv = simplify_gen_ternary (IF_THEN_ELSE, word_mode,
+ word_mode, temp,
+ const_true_rtx, equiv);
+ }
+ else
+ {
+ equiv = simplify_gen_relational (comparison, word_mode,
+ mode, x, y);
+ if (! FLOAT_LIB_COMPARE_RETURNS_BOOL (mode, comparison))
+ {
+ rtx true_rtx, false_rtx;
+
+ switch (comparison)
+ {
+ case EQ:
+ true_rtx = const0_rtx;
+ false_rtx = const_true_rtx;
+ break;
+
+ case NE:
+ true_rtx = const_true_rtx;
+ false_rtx = const0_rtx;
+ break;
+
+ case GT:
+ true_rtx = const1_rtx;
+ false_rtx = const0_rtx;
+ break;
+
+ case GE:
+ true_rtx = const0_rtx;
+ false_rtx = constm1_rtx;
+ break;
+
+ case LT:
+ true_rtx = constm1_rtx;
+ false_rtx = const0_rtx;
+ break;
+
+ case LE:
+ true_rtx = const0_rtx;
+ false_rtx = const1_rtx;
+ break;
+
+ default:
+ abort ();
+ }
+ equiv = simplify_gen_ternary (IF_THEN_ELSE, word_mode,
+ word_mode, equiv,
+ true_rtx, false_rtx);
+ }
+ }
+ set_unique_reg_note (last, REG_EQUAL, equiv);
+ }
+ }
+
if (comparison == UNORDERED
|| FLOAT_LIB_COMPARE_RETURNS_BOOL (mode, comparison))
comparison = NE;
- result = emit_library_call_value (libfunc, NULL_RTX, LCT_CONST_MAKE_BLOCK,
- word_mode, 2, x, mode, y, mode);
*px = result;
*py = const0_rtx;
*pmode = word_mode;
--
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