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2010-10-15 Chung-Lin Tang <cltang@codesourcery.com>
Backport from mainline:
2010-10-15 Chung-Lin Tang <cltang@codesourcery.com>
gcc/
* ifcvt.c (find_active_insn_before): New function.
(find_active_insn_after): New function.
(cond_exec_process_if_block): Use new functions to replace
prev_active_insn() and next_active_insn().
gcc/testsuite/
* gcc.dg/20101010-1.c: New testcase.
=== modified file 'gcc/ifcvt.c'
Index: gcc-4.5/gcc/ifcvt.c
===================================================================
--- gcc-4.5.orig/gcc/ifcvt.c
+++ gcc-4.5/gcc/ifcvt.c
@@ -88,6 +88,8 @@ static int count_bb_insns (const_basic_b
static bool cheap_bb_rtx_cost_p (const_basic_block, int);
static rtx first_active_insn (basic_block);
static rtx last_active_insn (basic_block, int);
+static rtx find_active_insn_before (basic_block, rtx);
+static rtx find_active_insn_after (basic_block, rtx);
static basic_block block_fallthru (basic_block);
static int cond_exec_process_insns (ce_if_block_t *, rtx, rtx, rtx, rtx, int);
static rtx cond_exec_get_condition (rtx);
@@ -230,6 +232,48 @@ last_active_insn (basic_block bb, int sk
return insn;
}
+/* Return the active insn before INSN inside basic block CURR_BB. */
+
+static rtx
+find_active_insn_before (basic_block curr_bb, rtx insn)
+{
+ if (!insn || insn == BB_HEAD (curr_bb))
+ return NULL_RTX;
+
+ while ((insn = PREV_INSN (insn)) != NULL_RTX)
+ {
+ if (NONJUMP_INSN_P (insn) || JUMP_P (insn) || CALL_P (insn))
+ break;
+
+ /* No other active insn all the way to the start of the basic block. */
+ if (insn == BB_HEAD (curr_bb))
+ return NULL_RTX;
+ }
+
+ return insn;
+}
+
+/* Return the active insn after INSN inside basic block CURR_BB. */
+
+static rtx
+find_active_insn_after (basic_block curr_bb, rtx insn)
+{
+ if (!insn || insn == BB_END (curr_bb))
+ return NULL_RTX;
+
+ while ((insn = NEXT_INSN (insn)) != NULL_RTX)
+ {
+ if (NONJUMP_INSN_P (insn) || JUMP_P (insn) || CALL_P (insn))
+ break;
+
+ /* No other active insn all the way to the end of the basic block. */
+ if (insn == BB_END (curr_bb))
+ return NULL_RTX;
+ }
+
+ return insn;
+}
+
/* Return the basic block reached by falling though the basic block BB. */
static basic_block
@@ -448,9 +492,9 @@ cond_exec_process_if_block (ce_if_block_
if (n_matching > 0)
{
if (then_end)
- then_end = prev_active_insn (then_first_tail);
+ then_end = find_active_insn_before (then_bb, then_first_tail);
if (else_end)
- else_end = prev_active_insn (else_first_tail);
+ else_end = find_active_insn_before (else_bb, else_first_tail);
n_insns -= 2 * n_matching;
}
@@ -488,9 +532,9 @@ cond_exec_process_if_block (ce_if_block_
if (n_matching > 0)
{
if (then_start)
- then_start = next_active_insn (then_last_head);
+ then_start = find_active_insn_after (then_bb, then_last_head);
if (else_start)
- else_start = next_active_insn (else_last_head);
+ else_start = find_active_insn_after (else_bb, else_last_head);
n_insns -= 2 * n_matching;
}
}
@@ -646,7 +690,7 @@ cond_exec_process_if_block (ce_if_block_
{
rtx from = then_first_tail;
if (!INSN_P (from))
- from = next_active_insn (from);
+ from = find_active_insn_after (then_bb, from);
delete_insn_chain (from, BB_END (then_bb), false);
}
if (else_last_head)
Index: gcc-4.5/gcc/testsuite/gcc.dg/20101010-1.c
===================================================================
--- /dev/null
+++ gcc-4.5/gcc/testsuite/gcc.dg/20101010-1.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-crossjumping" } */
+
+int foo (void)
+{
+ int len;
+ if (bar1 (&len))
+ {
+ char devpath [len];
+ if (bar2 (devpath) == len)
+ return len;
+ }
+ return -1;
+}
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