Similar idea to the combine.c and gcse.c patches.
2019-09-11 Richard Sandiford
gcc/
* loop-iv.c: Include regs.h and function-abi.h.
(simplify_using_initial_values): Use call_insn_abi to get the
ABI of the call insn target. Conservatively assume that
partially-clobbered registers are altered.
Index: gcc/loop-iv.c
===
--- gcc/loop-iv.c 2019-09-09 19:01:40.371078272 +0100
+++ gcc/loop-iv.c 2019-09-11 19:48:35.161764168 +0100
@@ -62,6 +62,8 @@ Free Software Foundation; either version
#include "dumpfile.h"
#include "rtl-iter.h"
#include "tree-ssa-loop-niter.h"
+#include "regs.h"
+#include "function-abi.h"
/* Possible return values of iv_get_reaching_def. */
@@ -1972,8 +1974,14 @@ simplify_using_initial_values (class loo
CLEAR_REG_SET (this_altered);
note_stores (insn, mark_altered, this_altered);
if (CALL_P (insn))
- /* Kill all call clobbered registers. */
- IOR_REG_SET_HRS (this_altered, regs_invalidated_by_call);
+ {
+ /* Kill all registers that might be clobbered by the call.
+We don't track modes of hard registers, so we need to be
+conservative and assume that partial kills are full kills. */
+ function_abi abi = call_insn_abi (insn);
+ IOR_REG_SET_HRS (this_altered,
+ abi.full_and_partial_reg_clobbers ());
+ }
if (suitable_set_for_replacement (insn, &dest, &src))
{
