Another RTL checking failure in ext-dce. An easy one to fix this time.
When we optimize an extension we have to go back and cleanup with
SUBREG_PROMOTED state. So we record the destination register into a
bitmap as we make changes, then later do a single pass over the IL
fixing any associated subreg expressions.
The optimization is changing the SET_SRC and largely ignores the
destination. The LHS could be a REG, SUBREG, or ZERO_EXTRACT. If the
LHS is a SUBREG or ZERO_EXTRACT we can just strip them.
Bootstrapped and ran the testsuite with an RTL checking compiler and
verified no ext-dce RTL checking failures tripped. Also bootstrapped
and regression tested x86_64 in the usual way.
Pushing to the trunk.
Jeff
commit cdc9cd4afe8949276a0c50215eb7f23e2086044f
Author: Jeff Law <j...@ventanamicro.com>
Date: Wed Aug 21 16:52:23 2024 -0600
[PR rtl-optimization/116437] Fix RTL checking issue in ext-dce
Another RTL checking failure in ext-dce. An easy one to fix this time.
When we optimize an extension we have to go back and cleanup with
SUBREG_PROMOTED state. So we record the destination register into a bitmap
as
we make changes, then later do a single pass over the IL fixing any
associated
subreg expressions.
The optimization is changing the SET_SRC and largely ignores the
destination.
The LHS could be a REG, SUBREG, or ZERO_EXTRACT. If the LHS is a SUBREG or
ZERO_EXTRACT we can just strip them.
Bootstrapped and ran the testsuite with an RTL checking compiler and
verified
no ext-dce RTL checking failures tripped. Also bootstrapped and regression
tested x86_64 in the usual way.
Pushing to the trunk.
PR rtl-optimization/116437
gcc/
* ext-dce.cc (ext_dce_try_optimize_insn): Handle SUBREG and
ZERO_EXTRACT destinations.
diff --git a/gcc/ext-dce.cc b/gcc/ext-dce.cc
index eee9208f0d6..35c06469b82 100644
--- a/gcc/ext-dce.cc
+++ b/gcc/ext-dce.cc
@@ -422,8 +422,13 @@ ext_dce_try_optimize_insn (rtx_insn *insn, rtx set)
{
int ok = validate_change (insn, &SET_SRC (set), new_pattern, false);
+ rtx x = SET_DEST (set);
+ while (SUBREG_P (x) || GET_CODE (x) == ZERO_EXTRACT)
+ x = XEXP (x, 0);
+
+ gcc_assert (REG_P (x));
if (ok)
- bitmap_set_bit (changed_pseudos, REGNO (SET_DEST (set)));
+ bitmap_set_bit (changed_pseudos, REGNO (x));
if (dump_file)
{
