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PATCH: Remove redundant instructions after regcprop
- From: "Paulo J. Matos" <paulo at matos-sorge dot com>
- To: gcc-patches at gcc dot gnu dot org
- Date: Thu, 02 Aug 2012 11:17:27 +0100
- Subject: PATCH: Remove redundant instructions after regcprop
Extended regcprop to check and remove for redundant move instructions
resulting from the pass.
Paulo.
2012-08-02 Paulo Matos <Paulo.Matos@csr.com>
* regcprop.c (copy_value): remove check for redundant moves.
* regcprop.c (copy_value): add check for redundant moves,
remove instructions if redundant.
--- //depot/bc/main/devHost/gcc46/gcc/gcc/regcprop.c 2011-09-06 14:29:15.000000000 0100
+++ /home/pm18/p4ws/pm18_binutils/bc/main/devHost/gcc46/gcc/gcc/regcprop.c 2011-09-06 14:29:15.000000000 0100
@@ -301,11 +301,8 @@
unsigned int dn, sn;
unsigned int i;
- /* ??? At present, it's possible to see noop sets. It'd be nice if
- this were cleaned up beforehand... */
- if (sr == dr)
- return;
-
+ gcc_assert(dr != sr);
+
/* Do not propagate copies to the stack pointer, as that can leave
memory accesses with no scheduling dependency on the stack update. */
if (dr == STACK_POINTER_REGNUM)
@@ -734,9 +731,9 @@
copyprop_hardreg_forward_1 (basic_block bb, struct value_data *vd)
{
bool anything_changed = false;
- rtx insn;
+ rtx insn, next;
- for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
+ FOR_BB_INSNS_SAFE(bb, insn, next)
{
int n_ops, i, alt, predicated;
bool is_asm, any_replacements;
@@ -755,10 +752,7 @@
insn, vd);
}
- if (insn == BB_END (bb))
- break;
- else
- continue;
+ continue;
}
set = single_set (insn);
@@ -966,10 +960,19 @@
/* Notice copies. */
if (set && REG_P (SET_DEST (set)) && REG_P (SET_SRC (set)))
- copy_value (SET_DEST (set), SET_SRC (set), vd);
-
- if (insn == BB_END (bb))
- break;
+ {
+ unsigned int dr = REGNO(SET_DEST(set));
+ unsigned int sr = REGNO(SET_SRC(set));
+
+ if(dr == sr)
+ {
+ /* noop set */
+ delete_insn_and_edges(insn);
+ }
+ else
+ copy_value (SET_DEST (set), SET_SRC (set), vd);
+ }
+
}
return anything_changed;