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Re: [PATCH][ARM]Use of vcvt for float to fixed point conversions.
- From: Ramana Radhakrishnan <ramrad01 at arm dot com>
- To: Renlin Li <Renlin dot Li at arm dot com>
- Cc: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>, Richard Earnshaw <Richard dot Earnshaw at arm dot com>
- Date: Wed, 04 Dec 2013 11:23:45 +0000
- Subject: Re: [PATCH][ARM]Use of vcvt for float to fixed point conversions.
- Authentication-results: sourceware.org; auth=none
- References: <528CE2F4 dot 9090906 at arm dot com>
Sorry about the slow response. Been on holiday.
On 20/11/13 16:27, Renlin Li wrote:
Hi all,
This patch will make the arm back-end use vcvt for float to fixed point
conversions when applicable.
Test on arm-none-linux-gnueabi has been done on the model.
Okay for trunk?
+ (define_insn "*combine_vcvtf2i"
+ [(set (match_operand:SI 0 "s_register_operand" "=r")
+ (fix:SI (fix:SF (mult:SF (match_operand:SF 1 "s_register_operand" "t")
+ (match_operand 2
+ "const_double_vcvt_power_of_two" "Dp")))))]
+ "TARGET_32BIT && TARGET_HARD_FLOAT && TARGET_VFP3 && !flag_rounding_math"
+ "vcvt%?.s32.f32\\t%1, %1, %v2\;vmov%?\\t%0, %1"
+ [(set_attr "predicable" "yes")
+ (set_attr "predicable_short_it" "no")
+ (set_attr "ce_count" "2")
+ (set_attr "type" "f_cvtf2i")]
+ )
+
You need to set length to 8.
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/fixed_float_conversion.c
@@ -0,0 +1,15 @@
+/* Check that vcvt is used for fixed and float data conversions. */
+/* { dg-do compile } */
+/* { dg-options "-O1 -mfpu=vfp3" } */
+/* { dg-require-effective-target arm_vfp_ok } */
+float fixed_to_float(int i)
+{
+ return ((float)i / (1 << 16));
+}
+
+int float_to_fixed(float f)
+{
+ return ((int)(f*(1 << 16)));
+}
+/* { dg-final { scan-assembler "vcvt.f32.s32" } } */
+/* { dg-final { scan-assembler "vcvt.s32.f32" } } */
GNU coding style for functions.
Ok with those changes.
regards
Ramana
Kind regards,
Renlin Li
gcc/ChangeLog:
2013-11-20 Renlin Li <Renlin.Li@arm.com>
* config/arm/arm-protos.h (vfp_const_double_for_bits): Declare.
* config/arm/constraints.md (Dp): Define new constraint.
* config/arm/predicates.md ( const_double_vcvt_power_of_two): Define
new predicate.
* config/arm/arm.c (arm_print_operand): Add print for new fucntion.
(vfp3_const_double_for_bits): New function.
* config/arm/vfp.md (combine_vcvtf2i): Define new instruction.
gcc/testsuite/ChangeLog:
2013-11-20 Renlin Li <Renlin.Li@arm.com>
* gcc.target/arm/fixed_float_conversion.c: New test case.