[PATCH v2 18/18] Check anti-dependence between 0 and 3 for loads

[Aleksandar Rakic]

From: Chao-ying Fu <c...@wavecomp.com>

gcc/
        * config/mips/mips.md (join2_load_store<JOIN_MODE:mode>): Check
        operand 0 and 3. Assert other two operands do not overlap after
        they are reordered.
        (*join2_loadhi): Same.

Cherry-picked 63175687761e51dfe2f75dfab7b4de7f44bb4abe
from https://github.com/MIPS/gcc

Signed-off-by: Chao-ying Fu <c...@mips.com>
Signed-off-by: Aleksandar Rakic <aleksandar.ra...@htecgroup.com>
---
 gcc/config/mips/mips.md | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/gcc/config/mips/mips.md b/gcc/config/mips/mips.md
index a69a879214e..db61b9d98fe 100644
--- a/gcc/config/mips/mips.md
+++ b/gcc/config/mips/mips.md
@@ -8060,7 +8060,7 @@
     /* Reg-renaming pass reuses base register if it is dead after bonded loads.
        Hardware does not bond those loads, even when they are consecutive.
        However, order of the loads need to be checked for correctness.  */
-    if (!load_p || !reg_overlap_mentioned_p (operands[0], operands[1]))
+    if (!load_p || !reg_overlap_mentioned_p (operands[0], operands[3]))
       {
        output_asm_insn (mips_output_move (insn, operands[0], operands[1]),
                         operands);
@@ -8069,6 +8069,8 @@
       }
     else
       {
+       /* Check the other two registers.  */
+       gcc_assert (!reg_overlap_mentioned_p (operands[2], operands[1]));
        output_asm_insn (mips_output_move (insn, operands[2], operands[3]),
                         &operands[2]);
        output_asm_insn (mips_output_move (insn, operands[0], operands[1]),
@@ -8123,13 +8125,15 @@
     /* Reg-renaming pass reuses base register if it is dead after bonded loads.
        Hardware does not bond those loads, even when they are consecutive.
        However, order of the loads need to be checked for correctness.  */
-    if (!reg_overlap_mentioned_p (operands[0], operands[1]))
+    if (!reg_overlap_mentioned_p (operands[0], operands[3]))
       {
        output_asm_insn ("lh<u>\t%0,%1", operands);
        output_asm_insn ("lh<u>\t%2,%3", operands);
       }
     else
       {
+       /* Check the other two registers.  */
+       gcc_assert (!reg_overlap_mentioned_p (operands[2], operands[1]));
        output_asm_insn ("lh<u>\t%2,%3", operands);
        output_asm_insn ("lh<u>\t%0,%1", operands);
       }
-- 
2.34.1