S/390 epilogue ends with (parallel [(return) (use %r14)]) instead of
the more usual (return) or (simple_return). This sequence is not
recognized by the conditional return logic in try_optimize_cfg ().
This was introduced for processors older than z196, where it is
sometimes profitable to use call-clobbered register for returning
instead of %r14. On newer processors we always return via %r14,
for which the fact that it's used is already reflected by
EPILOGUE_USES. In this case a simple (return) suffices.
This patch changes return_use () to emit simple (return)s when
returning via %r14. The resulting sequences are recognized by the
conditional return logic in try_optimize_cfg ().
gcc/ChangeLog:
2018-09-19 Ilya Leoshkevich
PR target/80080
* config/s390/s390.c (s390_emit_epilogue): Do not use PARALLEL
RETURN+USE when returning via %r14.
gcc/testsuite/ChangeLog:
2018-09-19 Ilya Leoshkevich
PR target/80080
* gcc.target/s390/risbg-ll-3.c: Expect conditional returns.
* gcc.target/s390/zvector/vec-cmp-2.c: Likewise.
---
gcc/config/s390/s390.c| 20 +---
gcc/testsuite/gcc.target/s390/risbg-ll-3.c| 6 +--
.../gcc.target/s390/zvector/vec-cmp-2.c | 48 +--
3 files changed, 41 insertions(+), 33 deletions(-)
diff --git a/gcc/config/s390/s390.c b/gcc/config/s390/s390.c
index 541b032ac63..71039fe6ce9 100644
--- a/gcc/config/s390/s390.c
+++ b/gcc/config/s390/s390.c
@@ -11082,7 +11082,7 @@ s390_emit_prologue (void)
void
s390_emit_epilogue (bool sibcall)
{
- rtx frame_pointer, return_reg, cfa_restores = NULL_RTX;
+ rtx frame_pointer, return_reg = NULL_RTX, cfa_restores = NULL_RTX;
int area_bottom, area_top, offset = 0;
int next_offset;
int i;
@@ -11191,10 +11191,6 @@ s390_emit_epilogue (bool sibcall)
}
- /* Return register. */
-
- return_reg = gen_rtx_REG (Pmode, RETURN_REGNUM);
-
/* Restore call saved gprs. */
if (cfun_frame_layout.first_restore_gpr != -1)
@@ -11284,7 +11280,19 @@ s390_emit_epilogue (bool sibcall)
s390_restore_gprs_from_fprs ();
if (! sibcall)
-emit_jump_insn (gen_return_use (return_reg));
+{
+ if (!return_reg && !s390_can_use_return_insn ())
+/* We planned to emit (return), be we are not allowed to. */
+return_reg = gen_rtx_REG (Pmode, RETURN_REGNUM);
+
+ if (return_reg)
+/* Emit (return) and (use). */
+emit_jump_insn (gen_return_use (return_reg));
+ else
+/* The fact that RETURN_REGNUM is used is already reflected by
+ EPILOGUE_USES. Emit plain (return). */
+emit_jump_insn (gen_return ());
+}
}
/* Implement TARGET_SET_UP_BY_PROLOGUE. */
diff --git a/gcc/testsuite/gcc.target/s390/risbg-ll-3.c
b/gcc/testsuite/gcc.target/s390/risbg-ll-3.c
index 838f1ffbd91..2a2db543cd9 100644
--- a/gcc/testsuite/gcc.target/s390/risbg-ll-3.c
+++ b/gcc/testsuite/gcc.target/s390/risbg-ll-3.c
@@ -23,7 +23,7 @@ i64 f1 (i64 v_a, i64 v_b)
extern i64 f2_foo();
i64 f2 (i64 v_a, i64 v_b)
{
-/* { dg-final { scan-assembler "f2:\n\trisbg\t%r2,%r3,60,62,0\n\tje\t" {
target { lp64 } } } } */
+/* { dg-final { scan-assembler
"f2:\n\trisbg\t%r2,%r3,60,62,0\n\tbner\t%r14\n\tjg\tf2_foo\n" { target { lp64 }
} } } */
/* { dg-final { scan-assembler
"f2:\n\trisbgn\t%r3,%r2,0,0\\\+32-1,64-0-32\n\trisbg\t%r3,%r5,60,62,0" { target
{ ! lp64 } } } } */
i64 v_anda = v_a & -15;
i64 v_andb = v_b & 14;
@@ -37,8 +37,8 @@ i64 f2 (i64 v_a, i64 v_b)
void f2_bar ();
void f2_cconly (i64 v_a, i64 v_b)
{
-/* { dg-final { scan-assembler "f2_cconly:\n\trisbg\t%r3,%r2,63,59,0\n\tjne\t"
{ target { lp64 } } } } */
-/* { dg-final { scan-assembler
"f2_cconly:\n\trisbgn\t%r3,%r2,0,0\\\+32-1,64-0-32\n\trisbg\t%r3,%r5,60,62,0\n\tjne\t"
{ target { ! lp64 } } } } */
+/* { dg-final { scan-assembler
"f2_cconly:\n\trisbg\t%r3,%r2,63,59,0\n\tber\t%r14\n\tjg\tf2_bar\n" { target {
lp64 } } } } */
+/* { dg-final { scan-assembler
"f2_cconly:\n\trisbgn\t%r3,%r2,0,0\\\+32-1,64-0-32\n\trisbg\t%r3,%r5,60,62,0\n\tber\t%r14\n\tjg\tf2_bar\n"
{ target { ! lp64 } } } } */
if ((v_a & -15) | (v_b & 14))
f2_bar();
}
diff --git a/gcc/testsuite/gcc.target/s390/zvector/vec-cmp-2.c
b/gcc/testsuite/gcc.target/s390/zvector/vec-cmp-2.c
index 1e63defa063..09a15eb25f0 100644
--- a/gcc/testsuite/gcc.target/s390/zvector/vec-cmp-2.c
+++ b/gcc/testsuite/gcc.target/s390/zvector/vec-cmp-2.c
@@ -15,7 +15,7 @@ all_eq_double (vector double a, vector double b)
if (__builtin_expect (vec_all_eq (a, b), 1))
g = 2;
}
-/* { dg-final { scan-assembler-times
all_eq_double:\n\tvfcedbs\t%v\[0-9\]*,%v24,%v26\n\tjne 1 } } */
+/* { dg-final { scan-assembler-times
all_eq_double:\n\tvfcedbs\t%v\[0-9\]*,%v24,%v26\n\tbner\t%r14\n 1 } } */
void __attribute__((noinline,noclone))
all_ne_double (vector double a, vector double b)
@@ -23,7 +23,7 @@ all_ne_double (vector double a, vector double b)
if (__builtin_expect (vec_all_ne
