Hi,
Some instructions (like one in PR63534) could have hidden use of PIC register.
Therefore we need to leave SET_GOT not deleted till reload completed.
The patch prevents SET_GOT from deleting while PIC register is pseudo.
Is it ok?
ChangeLog:
2014-10-17 Evgeny Stupachenko <evstu...@gmail.com>
PR target/63534
* cse.c (delete_trivially_dead_insns): Consider PIC register is used
while it is pseudo.
* dse.c (deletable_insn_p): Likewise.
diff --git a/gcc/cse.c b/gcc/cse.c
index be2f31b..062ba45 100644
--- a/gcc/cse.c
+++ b/gcc/cse.c
@@ -6953,6 +6953,11 @@ delete_trivially_dead_insns (rtx_insn *insns, int nreg)
/* If no debug insns can be present, COUNTS is just an array
which counts how many times each pseudo is used. */
}
+ /* Pseudo PIC register should be considered as used due to possible
+ new usages generated. */
+ if (pic_offset_table_rtx
+ && REGNO (pic_offset_table_rtx) >= FIRST_PSEUDO_REGISTER)
+ counts[REGNO (pic_offset_table_rtx)]++;
/* Go from the last insn to the first and delete insns that only set unused
registers or copy a register to itself. As we delete an insn, remove
usage counts for registers it uses.
diff --git a/gcc/dce.c b/gcc/dce.c
index 5b7d36e..a52a59c 100644
--- a/gcc/dce.c
+++ b/gcc/dce.c
@@ -127,6 +127,10 @@ deletable_insn_p (rtx_insn *insn, bool fast,
bitmap arg_stores)
if (HARD_REGISTER_NUM_P (DF_REF_REGNO (def))
&& global_regs[DF_REF_REGNO (def)])
return false;
+ /* Initialization of pseudo PIC register should never be removed. */
+ else if (DF_REF_REG (def) == pic_offset_table_rtx
+ && REGNO (pic_offset_table_rtx) >= FIRST_PSEUDO_REGISTER)
+ return false;
body = PATTERN (insn);
switch (GET_CODE (body))
