From b0ce92b4038fa29a390186c9eb03f1f1cfa8dd56 Mon Sep 17 00:00:00 2001
From: Michael Meissner <meissner@linux.vnet.ibm.com>
Date: Wed, 8 Dec 2010 16:34:20 +0000
Subject: [PATCH] PR 42694: add checks to make sure sqrt is supported
From-SVN: r167594
---
gcc/ChangeLog | 8 +++++
gcc/builtins.c | 6 ++--
gcc/testsuite/ChangeLog | 6 ++++
gcc/testsuite/gcc.target/powerpc/ppc-pow.c | 34 ++++++++++++++++++++++
4 files changed, 52 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/powerpc/ppc-pow.c
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 92b01db9ac87..64285702a357 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2010-12-08 Michael Meissner <meissner@linux.vnet.ibm.com>
+
+ PR middle-end/42694
+ * builtins.c (expand_builtin_pow_root): Don't optimize pow(x,y)
+ where y is 0.25, 1./6., or 0.75 if the target does not have a sqrt
+ instruction, but do optimize if y is 0.5 or 1./3. since that
+ changes an expensive call into a cheaper one.
+
2010-12-08 Richard Guenther <rguenther@suse.de>
* tree-ssa-sccvn.c (copy_reference_ops_from_ref): Use a shift
diff --git a/gcc/builtins.c b/gcc/builtins.c
index 2816a7e1e618..eb2aa3e6b343 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -3068,7 +3068,8 @@ expand_builtin_pow_root (location_t loc, tree arg0, tree arg1, tree type,
if (REAL_VALUES_EQUAL (c, dconsthalf))
op = build_call_nofold_loc (loc, sqrtfn, 1, arg0);
- else
+ /* Don't do this optimization if we don't have a sqrt insn. */
+ else if (optab_handler (sqrt_optab, mode) != CODE_FOR_nothing)
{
REAL_VALUE_TYPE dconst1_4 = dconst1;
REAL_VALUE_TYPE dconst3_4;
@@ -3114,7 +3115,8 @@ expand_builtin_pow_root (location_t loc, tree arg0, tree arg1, tree type,
op = build_call_nofold_loc (loc, cbrtfn, 1, arg0);
/* Now try 1/6. */
- else if (optimize_insn_for_speed_p ())
+ else if (optimize_insn_for_speed_p ()
+ && optab_handler (sqrt_optab, mode) != CODE_FOR_nothing)
{
REAL_VALUE_TYPE dconst1_6 = dconst1_3;
SET_REAL_EXP (&dconst1_6, REAL_EXP (&dconst1_6) - 1);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 8743d366b792..7a7f3be27cce 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2010-12-08 Michael Meissner <meissner@linux.vnet.ibm.com>
+
+ PR middle-end/42694
+ * gcc.target/powerpc/ppc-pow.c: New file to make sure pow (x,
+ 0.75) is not optimized if the machine has no sqrt instruction.
+
2010-12-07 Andrey Belevantsev <abel@ispras.ru>
PR target/43603
diff --git a/gcc/testsuite/gcc.target/powerpc/ppc-pow.c b/gcc/testsuite/gcc.target/powerpc/ppc-pow.c
new file mode 100644
index 000000000000..1255d5c5966f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/ppc-pow.c
@@ -0,0 +1,34 @@
+/* { dg-do compile { target { { powerpc*-*-* } && { ! powerpc*-apple-darwin* } } } } */
+/* { dg-options "-O2 -ffast-math -mcpu=power6" } */
+/* { dg-final { scan-assembler-times "fsqrt" 3 } } */
+/* { dg-final { scan-assembler-times "fmul" 1 } } */
+/* { dg-final { scan-assembler-times "bl pow" 1 } } */
+/* { dg-final { scan-assembler-times "bl sqrt" 1 } } */
+
+double
+do_pow_0_75_default (double a)
+{
+ return __builtin_pow (a, 0.75); /* should generate 2 fsqrts */
+}
+
+double
+do_pow_0_5_default (double a)
+{
+ return __builtin_pow (a, 0.5); /* should generate fsqrt */
+}
+
+#pragma GCC target "no-powerpc-gpopt,no-powerpc-gfxopt"
+
+double
+do_pow_0_75_nosqrt (double a)
+{
+ return __builtin_pow (a, 0.75); /* should call pow */
+}
+
+double
+do_pow_0_5_nosqrt (double a)
+{
+ return __builtin_pow (a, 0.5); /* should call sqrt */
+}
+
+#pragma GCC reset_options
--
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