Currently on GCC 4.8 and 4.9, constant pool entries for QImode, HImode and
SImode values are filled as 32-bit quantities. This works fine for little
endian system but gives some incorrect results for big endian system when the
value is accessed with a mode smaller than 32-bit in size. Suppose the case of
the value 0x1234 that is accessed as an HImode value. It would be output as 0x0
0x0 0x12 0x34 in a constant pool entry and the 16-bit load that would be done
would lead to the value 0x0 in register.
This patch makes the consttable_1 and consttable_2 pattern available to ARM as
well so that values are output according to their mode.
This is a backport of commit r218118.
*** gcc/ChangeLog ***
2015-01-14 Thomas Preud'homme <thomas.preudho...@arm.com>
Backport from mainline
2014-11-27 Thomas Preud'homme <thomas.preudho...@arm.com>
PR target/59593
* config/arm/arm.c (dump_minipool): dispatch to consttable pattern
based on mode size.
* config/arm/arm.md (consttable_1): Make it TARGET_EITHER.
(consttable_2): Make it TARGET_EITHER and move HFmode handling from
consttable_4 to it.
(consttable_4): Move HFmode handling to consttable_2 pattern.
*** gcc/testsuite/ChangeLog ***
2015-01-14 Thomas Preud'homme <thomas.preudho...@arm.com>
Backport from mainline
2014-11-27 Thomas Preud'homme <thomas.preudho...@arm.com>
PR target/59593
* gcc.target/arm/constant-pool.c: New test.
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 85372e5..eeaece8 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,16 @@
+2015-01-14 Thomas Preud'homme <thomas.preudho...@arm.com>
+
+ Backport from mainline
+ 2014-11-27 Thomas Preud'homme <thomas.preudho...@arm.com>
+
+ PR target/59593
+ * config/arm/arm.c (dump_minipool): dispatch to consttable pattern
+ based on mode size.
+ * config/arm/arm.md (consttable_1): Make it TARGET_EITHER.
+ (consttable_2): Make it TARGET_EITHER and move HFmode handling from
+ consttable_4 to it.
+ (consttable_4): Move HFmode handling to consttable_2 pattern.
+
2015-01-14 Marek Polacek <pola...@redhat.com>
Backport from mainline
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 5e2571c..67ef80b 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -16274,7 +16274,7 @@ dump_minipool (rtx scan)
fputc ('\n', dump_file);
}
- switch (mp->fix_size)
+ switch (GET_MODE_SIZE (mp->mode))
{
#ifdef HAVE_consttable_1
case 1:
diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index 8119387..93b25e9 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -12224,7 +12224,7 @@
(define_insn "consttable_1"
[(unspec_volatile [(match_operand 0 "" "")] VUNSPEC_POOL_1)]
- "TARGET_THUMB1"
+ "TARGET_EITHER"
"*
making_const_table = TRUE;
assemble_integer (operands[0], 1, BITS_PER_WORD, 1);
@@ -12237,14 +12237,23 @@
(define_insn "consttable_2"
[(unspec_volatile [(match_operand 0 "" "")] VUNSPEC_POOL_2)]
- "TARGET_THUMB1"
+ "TARGET_EITHER"
"*
- making_const_table = TRUE;
- gcc_assert (GET_MODE_CLASS (GET_MODE (operands[0])) != MODE_FLOAT);
- assemble_integer (operands[0], 2, BITS_PER_WORD, 1);
- assemble_zeros (2);
- return \"\";
- "
+ {
+ rtx x = operands[0];
+ making_const_table = TRUE;
+ switch (GET_MODE_CLASS (GET_MODE (x)))
+ {
+ case MODE_FLOAT:
+ arm_emit_fp16_const (x);
+ break;
+ default:
+ assemble_integer (operands[0], 2, BITS_PER_WORD, 1);
+ assemble_zeros (2);
+ break;
+ }
+ return \"\";
+ }"
[(set_attr "length" "4")
(set_attr "type" "no_insn")]
)
@@ -12259,15 +12268,12 @@
switch (GET_MODE_CLASS (GET_MODE (x)))
{
case MODE_FLOAT:
- if (GET_MODE (x) == HFmode)
- arm_emit_fp16_const (x);
- else
- {
- REAL_VALUE_TYPE r;
- REAL_VALUE_FROM_CONST_DOUBLE (r, x);
- assemble_real (r, GET_MODE (x), BITS_PER_WORD);
- }
- break;
+ {
+ REAL_VALUE_TYPE r;
+ REAL_VALUE_FROM_CONST_DOUBLE (r, x);
+ assemble_real (r, GET_MODE (x), BITS_PER_WORD);
+ break;
+ }
default:
/* XXX: Sometimes gcc does something really dumb and ends up with
a HIGH in a constant pool entry, usually because it's trying to
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 222716d..49d1a73 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2015-01-14 Thomas Preud'homme <thomas.preudho...@arm.com>
+
+ Backport from mainline
+ 2014-11-27 Thomas Preud'homme <thomas.preudho...@arm.com>
+
+ PR target/59593
+ * gcc.target/arm/constant-pool.c: New test.
+
2015-01-14 Marek Polacek <pola...@redhat.com>
Backport from mainline
diff --git a/gcc/testsuite/gcc.target/arm/constant-pool.c
b/gcc/testsuite/gcc.target/arm/constant-pool.c
new file mode 100644
index 0000000..8427dfb
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/constant-pool.c
@@ -0,0 +1,27 @@
+/* { dg-do run } */
+/* { dg-options "-O1" } */
+
+unsigned short v = 0x5678;
+int i;
+int j = 0;
+int *ptr = &j;
+
+int
+func (void)
+{
+ for (i = 0; i < 1; ++i)
+ {
+ *ptr = -1;
+ v = 0x1234;
+ }
+ return v;
+}
+
+int
+main (void)
+{
+ func ();
+ if (v != 0x1234)
+ __builtin_abort ();
+ return 0;
+}
Is this ok for 4.8 and 4.9 branches?
Best regards,
Thomas
