Latest patch for r2 to r4, including a test case.
Ciao
Dominik ^_^ ^_^
--
Dominik Vogt
IBM Germany
gcc/ChangeLog
* config/s390/s390.c (s390_init_frame_layout): Try r4 to r2 for the
literal pool pointer.
gcc/testsuite/ChangeLog
* gcc.target/s390/litpool-r3-1.c: New test.
>From 67073c8b769e857d709f5e613919a6fe0120202e Mon Sep 17 00:00:00 2001
From: Dominik Vogt <v...@linux.vnet.ibm.com>
Date: Fri, 11 Dec 2015 11:33:23 +0100
Subject: [PATCH] S/390: Allow to use r2 to r4 as literal pool base
pointer.
The old code only considered r5 and r13.
---
gcc/config/s390/s390.c | 13 ++++++++++---
gcc/testsuite/gcc.target/s390/litpool-r3-1.c | 16 ++++++++++++++++
2 files changed, 26 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/s390/litpool-r3-1.c
diff --git a/gcc/config/s390/s390.c b/gcc/config/s390/s390.c
index ed684af..cba88bb 100644
--- a/gcc/config/s390/s390.c
+++ b/gcc/config/s390/s390.c
@@ -9584,10 +9584,17 @@ s390_init_frame_layout (void)
as base register to avoid save/restore overhead. */
if (!base_used)
cfun->machine->base_reg = NULL_RTX;
- else if (crtl->is_leaf && !df_regs_ever_live_p (5))
- cfun->machine->base_reg = gen_rtx_REG (Pmode, 5);
else
- cfun->machine->base_reg = gen_rtx_REG (Pmode, BASE_REGNUM);
+ {
+ int br = 0;
+
+ if (crtl->is_leaf)
+ /* Prefer r5 (most likely to be free). */
+ for (br = 5; br >= 2 && df_regs_ever_live_p (br); br--)
+ ;
+ cfun->machine->base_reg =
+ gen_rtx_REG (Pmode, (br > 0) ? br : BASE_REGNUM);
+ }
s390_register_info ();
s390_frame_info ();
diff --git a/gcc/testsuite/gcc.target/s390/litpool-r3-1.c b/gcc/testsuite/gcc.target/s390/litpool-r3-1.c
new file mode 100644
index 0000000..8ee50cf
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/litpool-r3-1.c
@@ -0,0 +1,16 @@
+/* Validate that r3 may be used as the literal pool pointer. Test that only on
+ 64-bit for z900 to simplify the test. It's not really different on 31-bit
+ or other cpus. */
+
+/* { dg-do compile { target { lp64 } } } */
+/* { dg-options "-march=z900 -O2" } */
+
+__int128 gi;
+const int c = 0x12345678u;
+int foo(void)
+{
+ gi += c;
+ return c;
+}
+
+/* { dg-final { scan-assembler-times "\tlarl\t%r3,.L3" 1 } } */
--
2.3.0
