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When lra-remat rematerializes an instruction with a clobber, it checks that the clobber does not kill live registers.

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When lra-remat rematerializes an instruction with a clobber, it checks
that the clobber does not kill live registers.  However it fails to check
that the clobber also doesn't overlap with the destination register of the
final rematerialized instruction.  As a result it is possible to generate
illegal instructions with the same hard register as the destination and a
clobber.  Fix this by also checking for overlaps with the destination
register.

    gcc/
	PR rtl-optimization/80754
	* lra-remat.c (do_remat): Add overlap checks for dst_regno.

From-SVN: r248424
This commit is contained in:
Wilco Dijkstra 2017-05-24 17:06:55 +00:00 committed by Wilco Dijkstra
parent c0edbb32c1
commit 1a2fa2f821
2 changed files with 24 additions and 3 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2017-05-24 Wilco Dijkstra <wdijkstr@arm.com>
PR rtl-optimization/80754
* lra-remat.c (do_remat): Add overlap checks for dst_regno.
2017-05-24 Sheldon Lobo <smlobo@sheldon.us.oracle.com>
* config/sparc/sparc.md (length): Return the correct value for -mflat

22
gcc/lra-remat.c
View File

@ -1117,6 +1117,7 @@ do_remat (void)
break;
}
int i, hard_regno, nregs;
int dst_hard_regno, dst_nregs;
rtx_insn *remat_insn = NULL;
HOST_WIDE_INT cand_sp_offset = 0;
if (cand != NULL)
@ -1131,6 +1132,12 @@ do_remat (void)
gcc_assert (REG_P (saved_op));
int ignore_regno = REGNO (saved_op);
dst_hard_regno = dst_regno < FIRST_PSEUDO_REGISTER
? dst_regno : reg_renumber[dst_regno];
gcc_assert (dst_hard_regno >= 0);
machine_mode mode = GET_MODE (SET_DEST (set));
dst_nregs = hard_regno_nregs[dst_hard_regno][mode];
for (reg = cand_id->regs; reg != NULL; reg = reg->next)
if (reg->type != OP_IN && reg->regno != ignore_regno)
{
@ -1141,6 +1148,10 @@ do_remat (void)
break;
if (i < nregs)
break;
/* Ensure the clobber also doesn't overlap dst_regno. */
if (hard_regno + nregs > dst_hard_regno
&& hard_regno < dst_hard_regno + dst_nregs)
break;
}
if (reg == NULL)
@ -1148,9 +1159,14 @@ do_remat (void)
for (reg = static_cand_id->hard_regs;
reg != NULL;
reg = reg->next)
if (reg->type != OP_IN
&& TEST_HARD_REG_BIT (live_hard_regs, reg->regno))
break;
if (reg->type != OP_IN)
{
if (TEST_HARD_REG_BIT (live_hard_regs, reg->regno))
break;
if (reg->regno >= dst_hard_regno
&& reg->regno < dst_hard_regno + dst_nregs)
break;
}
}
if (reg == NULL)