Altera requested us to extend the set of custom floating-point
instructions supported by the Nios II back end to include a round
instruction, with semantics matching the __builtin_lroundf function.
The basic machinery for this is already in place for the existing custom
instructions, so much of this patch is cut-and-paste.
The one new complication is that GCC doesn't use an inline expansion for
this builtin unless -fno-math-errno is also specified, so I made the
back end check for that as well as documenting the limitation. Some of
the other custom instructions already have similar restrictions
requiring -ffinite-math-only, etc., so that part was also just following
current practice and building on existing framework, just adding a new flag.
I've checked this in.
-Sandra
2014-04-22 Sandra Loosemore <san...@codesourcery.com>
gcc/
* config/nios2/nios2.md (UNSPEC_ROUND): New.
(lroundsfsi2): New.
* config/nios2/nios2.opt (mno-custom-round, mcustom-round=): New.
* config/nios2/nios2-opts.h (N2FPU_ALL_CODES): Add round.
* config/nios2/nios2.c (N2F_NO_ERRNO): Define.
(nios2_fpu_insn): Add entry for round.
(N2FPU_NO_ERRNO_P): Define.
(nios2_custom_check_insns): Add check for N2F_NO_ERRNO and
flag_errno_math.
* doc/invoke.texi (Nios II Options): Document -mcustom-round.
gcc/testsuite/
* gcc.target/nios2/custom-fp-conversion.c: Adjust to test that
lroundf generates custom round instruction, too.
Index: gcc/config/nios2/nios2.md
===================================================================
--- gcc/config/nios2/nios2.md (revision 209669)
+++ gcc/config/nios2/nios2.md (working copy)
@@ -70,6 +70,7 @@
UNSPEC_FATAN
UNSPEC_FEXP
UNSPEC_FLOG
+ UNSPEC_ROUND
UNSPEC_LOAD_GOT_REGISTER
UNSPEC_PIC_SYM
UNSPEC_PIC_CALL_SYM
@@ -585,6 +586,13 @@
{ return nios2_fpu_insn_asm (n2fpu_fix<f><i>); }
[(set_attr "type" "custom")])
+(define_insn "lroundsfsi2"
+ [(set (match_operand:SI 0 "register_operand" "=r")
+ (unspec:SI [(match_operand:SF 1 "general_operand" "r")] UNSPEC_ROUND))]
+ "nios2_fpu_insn_enabled (n2fpu_round)"
+ { return nios2_fpu_insn_asm (n2fpu_round); }
+ [(set_attr "type" "custom")])
+
(define_insn "extendsfdf2"
[(set (match_operand:DF 0 "register_operand" "=r")
(float_extend:DF (match_operand:SF 1 "general_operand" "r")))]
Index: gcc/config/nios2/nios2.opt
===================================================================
--- gcc/config/nios2/nios2.opt (revision 209669)
+++ gcc/config/nios2/nios2.opt (working copy)
@@ -529,3 +529,13 @@ Do not use the fwrx custom instruction
mcustom-fwrx=
Target Report RejectNegative Joined UInteger Var(nios2_custom_fwrx) Init(-1)
Integer id (N) of fwrx custom instruction
+
+mno-custom-round
+Target Report RejectNegative Var(nios2_custom_round, -1)
+Do not use the round custom instruction
+
+mcustom-round=
+Target Report RejectNegative Joined UInteger Var(nios2_custom_round) Init(-1)
+Integer id (N) of round custom instruction
+
+
Index: gcc/config/nios2/nios2-opts.h
===================================================================
--- gcc/config/nios2/nios2-opts.h (revision 209669)
+++ gcc/config/nios2/nios2-opts.h (working copy)
@@ -42,7 +42,7 @@ along with GCC; see the file COPYING3.
\
N2FPU_CODE(floatis) N2FPU_CODE(floatus) \
N2FPU_CODE(floatid) N2FPU_CODE(floatud) \
- N2FPU_CODE(fixsi) N2FPU_CODE(fixsu) \
+ N2FPU_CODE(round) N2FPU_CODE(fixsi) N2FPU_CODE(fixsu) \
N2FPU_CODE(fixdi) N2FPU_CODE(fixdu) \
N2FPU_CODE(fextsd) N2FPU_CODE(ftruncds) \
\
Index: gcc/config/nios2/nios2.c
===================================================================
--- gcc/config/nios2/nios2.c (revision 209669)
+++ gcc/config/nios2/nios2.c (working copy)
@@ -192,6 +192,7 @@ struct nios2_fpu_insn_info
#define N2F_DFREQ 0x2
#define N2F_UNSAFE 0x4
#define N2F_FINITE 0x8
+#define N2F_NO_ERRNO 0x10
unsigned int flags;
enum insn_code icode;
enum nios2_ftcode ftcode;
@@ -274,6 +275,7 @@ struct nios2_fpu_insn_info nios2_fpu_ins
N2FPU_INSN_DEF_BASE (floatus, 2, 0, floatunssisf2, (SF, UI)),
N2FPU_INSN_DEF_BASE (floatid, 2, 0, floatsidf2, (DF, SI)),
N2FPU_INSN_DEF_BASE (floatud, 2, 0, floatunssidf2, (DF, UI)),
+ N2FPU_INSN_DEF_BASE (round, 2, N2F_NO_ERRNO, lroundsfsi2, (SI, SF)),
N2FPU_INSN_DEF_BASE (fixsi, 2, 0, fix_truncsfsi2, (SI, SF)),
N2FPU_INSN_DEF_BASE (fixsu, 2, 0, fixuns_truncsfsi2, (UI, SF)),
N2FPU_INSN_DEF_BASE (fixdi, 2, 0, fix_truncdfsi2, (SI, DF)),
@@ -298,6 +300,7 @@ struct nios2_fpu_insn_info nios2_fpu_ins
#define N2FPU_FTCODE(code) (N2FPU(code).ftcode)
#define N2FPU_FINITE_P(code) (N2FPU(code).flags & N2F_FINITE)
#define N2FPU_UNSAFE_P(code) (N2FPU(code).flags & N2F_UNSAFE)
+#define N2FPU_NO_ERRNO_P(code) (N2FPU(code).flags & N2F_NO_ERRNO)
#define N2FPU_DOUBLE_P(code) (N2FPU(code).flags & N2F_DF)
#define N2FPU_DOUBLE_REQUIRED_P(code) (N2FPU(code).flags & N2F_DFREQ)
@@ -844,6 +847,15 @@ nios2_custom_check_insns (void)
warning (0, "switch %<-mcustom-%s%> has no effect unless "
"-ffinite-math-only is specified", N2FPU_NAME (i));
+ /* Warn if the user is trying to use a custom rounding instruction
+ that won't get used without -fno-math-errno. See
+ expand_builtin_int_roundingfn_2 () in builtins.c. */
+ if (flag_errno_math)
+ for (i = 0; i < ARRAY_SIZE (nios2_fpu_insn); i++)
+ if (N2FPU_ENABLED_P (i) && N2FPU_NO_ERRNO_P (i))
+ warning (0, "switch %<-mcustom-%s%> has no effect unless "
+ "-fno-math-errno is specified", N2FPU_NAME (i));
+
if (errors || custom_code_conflict)
fatal_error ("conflicting use of -mcustom switches, target attributes, "
"and/or __builtin_custom_ functions");
Index: gcc/doc/invoke.texi
===================================================================
--- gcc/doc/invoke.texi (revision 209669)
+++ gcc/doc/invoke.texi (working copy)
@@ -18485,6 +18485,12 @@ Conversion from double precision to sing
Conversion from floating point to signed or unsigned integer types, with
truncation towards zero.
+@item @samp{round}
+Conversion from single-precision floating point to signed integer,
+rounding to the nearest integer and ties away from zero.
+This corresponds to the @code{__builtin_lroundf} function when
+@option{-fno-math-errno} is used.
+
@item @samp{floatis}, @samp{floatus}, @samp{floatid}, @samp{floatud}
Conversion from signed or unsigned integer types to floating-point types.
Index: gcc/testsuite/gcc.target/nios2/custom-fp-conversion.c
===================================================================
--- gcc/testsuite/gcc.target/nios2/custom-fp-conversion.c (revision 209669)
+++ gcc/testsuite/gcc.target/nios2/custom-fp-conversion.c (working copy)
@@ -1,10 +1,11 @@
/* Test generation of conversion custom instructions. */
/* { dg-do compile } */
-/* { dg-options "-O1 -ffinite-math-only -funsafe-math-optimizations" } */
+/* { dg-options "-O1 -ffinite-math-only -funsafe-math-optimizations -fno-math-errno" } */
/* -O1 in the options is significant. Without it FP operations may not be
- optimized to custom instructions. */
+ optimized to custom instructions. Also, -fno-math-errno is required
+ to inline lroundf. */
#include <stdio.h>
#include <math.h>
@@ -25,6 +26,8 @@
#pragma GCC target ("custom-floatud=107")
#pragma GCC target ("custom-floatus=108")
#pragma GCC target ("custom-ftruncds=109")
+#pragma GCC target ("custom-round=110")
+
typedef struct data {
double fextsd;
@@ -37,6 +40,7 @@ typedef struct data {
double floatud;
float floatus;
float ftruncds;
+ int round;
} data_t;
void
@@ -52,6 +56,7 @@ custom_fp (int i, unsigned u, float f, d
out->floatud = (double) u;
out->floatus = (float) u;
out->ftruncds = (float) d;
+ out->round = lroundf (f);
}
/* { dg-final { scan-assembler "custom\\t100, .* # fextsd .*" } } */
@@ -64,3 +69,4 @@ custom_fp (int i, unsigned u, float f, d
/* { dg-final { scan-assembler "custom\\t107, .* # floatud .*" } } */
/* { dg-final { scan-assembler "custom\\t108, .* # floatus .*" } } */
/* { dg-final { scan-assembler "custom\\t109, .* # ftruncds .*" } } */
+/* { dg-final { scan-assembler "custom\\t110, .* # round .*" } } */
