#include "toplev.h"
#include "output.h"
#include "ggc.h"
+#include "timevar.h"
/* The basic idea of common subexpression elimination is to go
through the code, keeping a record of expressions that would
& HASH_MASK), mode_arg0))
&& p0->first_same_value == p1->first_same_value))
{
- /* Sadly two equal NaNs are not equivalent. */
- if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
- || ! FLOAT_MODE_P (mode_arg0)
- || flag_unsafe_math_optimizations)
- return ((code == EQ || code == LE || code == GE
- || code == LEU || code == GEU || code == UNEQ
- || code == UNLE || code == UNGE || code == ORDERED)
- ? true_rtx : false_rtx);
- /* Take care for the FP compares we can resolve. */
- if (code == UNEQ || code == UNLE || code == UNGE)
- return true_rtx;
- if (code == LTGT || code == LT || code == GT)
- return false_rtx;
+ /* Sadly two equal NaNs are not equivalent. */
+ if (!HONOR_NANS (mode_arg0))
+ return ((code == EQ || code == LE || code == GE
+ || code == LEU || code == GEU || code == UNEQ
+ || code == UNLE || code == UNGE
+ || code == ORDERED)
+ ? true_rtx : false_rtx);
+ /* Take care for the FP compares we can resolve. */
+ if (code == UNEQ || code == UNLE || code == UNGE)
+ return true_rtx;
+ if (code == LTGT || code == LT || code == GT)
+ return false_rtx;
}
/* If FOLDED_ARG0 is a register, see if the comparison we are
move dead invariants out of loops or make givs for dead quantities. The
remaining passes of the compilation are also sped up. */
-void
-delete_trivially_dead_insns (insns, nreg, preserve_basic_blocks)
+int
+delete_trivially_dead_insns (insns, nreg)
rtx insns;
int nreg;
- int preserve_basic_blocks;
{
int *counts;
rtx insn, prev;
- int i;
int in_libcall = 0, dead_libcall = 0;
- basic_block bb;
+ int ndead = 0, nlastdead, niterations = 0;
+ timevar_push (TV_DELETE_TRIVIALLY_DEAD);
/* First count the number of times each register is used. */
counts = (int *) xcalloc (nreg, sizeof (int));
for (insn = next_real_insn (insns); insn; insn = next_real_insn (insn))
count_reg_usage (insn, counts, NULL_RTX, 1);
- /* Go from the last insn to the first and delete insns that only set unused
- registers or copy a register to itself. As we delete an insn, remove
- usage counts for registers it uses.
-
- The first jump optimization pass may leave a real insn as the last
- insn in the function. We must not skip that insn or we may end
- up deleting code that is not really dead. */
- insn = get_last_insn ();
- if (! INSN_P (insn))
- insn = prev_real_insn (insn);
-
- if (!preserve_basic_blocks)
- for (; insn; insn = prev)
- {
- int live_insn = 0;
-
- prev = prev_real_insn (insn);
-
- /* Don't delete any insns that are part of a libcall block unless
- we can delete the whole libcall block.
-
- Flow or loop might get confused if we did that. Remember
- that we are scanning backwards. */
- if (find_reg_note (insn, REG_RETVAL, NULL_RTX))
- {
- in_libcall = 1;
- live_insn = 1;
- dead_libcall = dead_libcall_p (insn);
- }
- else if (in_libcall)
- live_insn = ! dead_libcall;
- else
- live_insn = insn_live_p (insn, counts);
-
- /* If this is a dead insn, delete it and show registers in it aren't
- being used. */
-
- if (! live_insn)
- {
- count_reg_usage (insn, counts, NULL_RTX, -1);
- delete_related_insns (insn);
- }
+ do
+ {
+ nlastdead = ndead;
+ niterations++;
+ /* Go from the last insn to the first and delete insns that only set unused
+ registers or copy a register to itself. As we delete an insn, remove
+ usage counts for registers it uses.
+
+ The first jump optimization pass may leave a real insn as the last
+ insn in the function. We must not skip that insn or we may end
+ up deleting code that is not really dead. */
+ insn = get_last_insn ();
+ if (! INSN_P (insn))
+ insn = prev_real_insn (insn);
- if (find_reg_note (insn, REG_LIBCALL, NULL_RTX))
- {
- in_libcall = 0;
- dead_libcall = 0;
- }
- }
- else
- for (i = 0; i < n_basic_blocks; i++)
- for (bb = BASIC_BLOCK (i), insn = bb->end; insn != bb->head; insn = prev)
+ for (; insn; insn = prev)
{
int live_insn = 0;
- prev = PREV_INSN (insn);
- if (!INSN_P (insn))
- continue;
+ prev = prev_real_insn (insn);
/* Don't delete any insns that are part of a libcall block unless
we can delete the whole libcall block.
if (! live_insn)
{
count_reg_usage (insn, counts, NULL_RTX, -1);
- delete_insn (insn);
+ delete_insn_and_edges (insn);
+ ndead++;
}
if (find_reg_note (insn, REG_LIBCALL, NULL_RTX))
dead_libcall = 0;
}
}
+ } while (ndead != nlastdead);
+ if (rtl_dump_file && ndead)
+ fprintf (rtl_dump_file, "Deleted %i trivially dead insns; %i iterations\n",
+ ndead, niterations);
/* Clean up. */
free (counts);
+ timevar_pop (TV_DELETE_TRIVIALLY_DEAD);
+ return ndead;
}
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