diff options
| -rw-r--r-- | gcc/cse.cc | 51 |
1 files changed, 27 insertions, 24 deletions
@@ -4623,6 +4623,7 @@ cse_insn (rtx_insn *insn) rtx src_eqv_here; rtx src_const = 0; rtx src_related = 0; + rtx dest_related = 0; bool src_related_is_const_anchor = false; struct table_elt *src_const_elt = 0; int src_cost = MAX_COST; @@ -5094,10 +5095,11 @@ cse_insn (rtx_insn *insn) src_related = 0; /* This is the same as the destination of the insns, we want - to prefer it. Copy it to src_related. The code below will - then give it a negative cost. */ - if (GET_CODE (dest) == code && rtx_equal_p (p->exp, dest)) - src_related = p->exp; + to prefer it. The code below will then give it a negative + cost. */ + if (!dest_related + && GET_CODE (dest) == code && rtx_equal_p (p->exp, dest)) + dest_related = p->exp; } /* Find the cheapest valid equivalent, trying all the available @@ -5139,27 +5141,28 @@ cse_insn (rtx_insn *insn) } } - if (src_related) + if (dest_related) { - if (rtx_equal_p (src_related, dest)) - src_related_cost = src_related_regcost = -1; - else - { - src_related_cost = COST (src_related, mode); - src_related_regcost = approx_reg_cost (src_related); - - /* If a const-anchor is used to synthesize a constant that - normally requires multiple instructions then slightly prefer - it over the original sequence. These instructions are likely - to become redundant now. We can't compare against the cost - of src_eqv_here because, on MIPS for example, multi-insn - constants have zero cost; they are assumed to be hoisted from - loops. */ - if (src_related_is_const_anchor - && src_related_cost == src_cost - && src_eqv_here) - src_related_cost--; - } + src_related_cost = src_related_regcost = -1; + /* Handle it as src_related. */ + src_related = dest_related; + } + else if (src_related) + { + src_related_cost = COST (src_related, mode); + src_related_regcost = approx_reg_cost (src_related); + + /* If a const-anchor is used to synthesize a constant that + normally requires multiple instructions then slightly prefer + it over the original sequence. These instructions are likely + to become redundant now. We can't compare against the cost + of src_eqv_here because, on MIPS for example, multi-insn + constants have zero cost; they are assumed to be hoisted from + loops. */ + if (src_related_is_const_anchor + && src_related_cost == src_cost + && src_eqv_here) + src_related_cost--; } /* If this was an indirect jump insn, a known label will really be |