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[PATCH][Committed] Add new ppc fma test
- From: Michael Meissner <meissner at linux dot vnet dot ibm dot com>
- To: gcc-patches at gcc dot gnu dot org, dje dot gcc at gmail dot com
- Date: Tue, 30 Nov 2010 15:36:13 -0500
- Subject: [PATCH][Committed] Add new ppc fma test
I committed this test case as obvious to make sure some common code for FFT's
continues to generate two FMA instructions, instead of a common multiply and
then add/subtract.
2010-11-30 Michael Meissner <meissner@linux.vnet.ibm.com>
* gcc.target/powerpc/ppc-fma-7.c: New file, test that (a*b)+c and
(a*b)-c generates two fma instructions, instead of separate
multiply, add, and subtract.
Index: gcc/testsuite/gcc.target/powerpc/ppc-fma-7.c
===================================================================
--- gcc/testsuite/gcc.target/powerpc/ppc-fma-7.c (revision 0)
+++ gcc/testsuite/gcc.target/powerpc/ppc-fma-7.c (revision 0)
@@ -0,0 +1,18 @@
+/* { dg-do compile { target { powerpc*-*-* } } } */
+/* { dg-skip-if "" { powerpc*-*-darwin* } { "*" } { "" } } */
+/* { dg-require-effective-target powerpc_altivec_ok } */
+/* { dg-options "-O3 -ftree-vectorize -mcpu=power6 -ffast-math" } */
+/* { dg-final { scan-assembler-times "fmadd" 1 } } */
+/* { dg-final { scan-assembler-times "fmsub " 1 } } */
+/* { dg-final { scan-assembler-not "fmul" } } */
+/* { dg-final { scan-assembler-not "fadd " } } */
+
+/* Check whether the common FFT idiom (a*b)+c and (a*b)-c generates two fma
+ instructions, instead of a multiply, add, and subtract. */
+
+void
+fft (double *result, double a, double b, double c)
+{
+ result[0] = (a*b) + c;
+ result[1] = (a*b) - c;
+}
--
Michael Meissner, IBM
5 Technology Place Drive, M/S 2757, Westford, MA 01886-3141, USA
meissner@linux.vnet.ibm.com fax +1 (978) 399-6899