Hi,
This patch disables gimple folding for float or double vec_min/max when
fast-math is not set. It makes vec_min/max conform with the guide.
Bootstrapped and tested on powerpc64le-linux with no regressions. Is this okay
for trunk? Any recommendations? Thanks a lot.
I re-send the patch as previous one is messed up in email thread. Sorry for
that.
ChangeLog
2021-08-25 Haochen Gui <guih...@linux.ibm.com>
gcc/
* config/rs6000/rs6000-call.c (rs6000_gimple_fold_builtin):
Modify the VSX_BUILTIN_XVMINDP, ALTIVEC_BUILTIN_VMINFP,
VSX_BUILTIN_XVMAXDP, ALTIVEC_BUILTIN_VMAXFP expansions.
gcc/testsuite/
* gcc.target/powerpc/vec-minmax-1.c: New test.
* gcc.target/powerpc/vec-minmax-2.c: Likewise.
patch.diff
diff --git a/gcc/config/rs6000/rs6000-call.c b/gcc/config/rs6000/rs6000-call.c
index b4e13af4dc6..90527734ceb 100644
--- a/gcc/config/rs6000/rs6000-call.c
+++ b/gcc/config/rs6000/rs6000-call.c
@@ -12159,6 +12159,11 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator *gsi)
return true;
/* flavors of vec_min. */
case VSX_BUILTIN_XVMINDP:
+ case ALTIVEC_BUILTIN_VMINFP:
+ if (!flag_finite_math_only || flag_signed_zeros)
+ return false;
+ /* Fall through to MIN_EXPR. */
+ gcc_fallthrough ();
case P8V_BUILTIN_VMINSD:
case P8V_BUILTIN_VMINUD:
case ALTIVEC_BUILTIN_VMINSB:
@@ -12167,7 +12172,6 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator *gsi)
case ALTIVEC_BUILTIN_VMINUB:
case ALTIVEC_BUILTIN_VMINUH:
case ALTIVEC_BUILTIN_VMINUW:
- case ALTIVEC_BUILTIN_VMINFP:
arg0 = gimple_call_arg (stmt, 0);
arg1 = gimple_call_arg (stmt, 1);
lhs = gimple_call_lhs (stmt);
@@ -12177,6 +12181,11 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator *gsi)
return true;
/* flavors of vec_max. */
case VSX_BUILTIN_XVMAXDP:
+ case ALTIVEC_BUILTIN_VMAXFP:
+ if (!flag_finite_math_only || flag_signed_zeros)
+ return false;
+ /* Fall through to MAX_EXPR. */
+ gcc_fallthrough ();
case P8V_BUILTIN_VMAXSD:
case P8V_BUILTIN_VMAXUD:
case ALTIVEC_BUILTIN_VMAXSB:
@@ -12185,7 +12194,6 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator *gsi)
case ALTIVEC_BUILTIN_VMAXUB:
case ALTIVEC_BUILTIN_VMAXUH:
case ALTIVEC_BUILTIN_VMAXUW:
- case ALTIVEC_BUILTIN_VMAXFP:
arg0 = gimple_call_arg (stmt, 0);
arg1 = gimple_call_arg (stmt, 1);
lhs = gimple_call_lhs (stmt);
diff --git a/gcc/testsuite/gcc.target/powerpc/vec-minmax-1.c
b/gcc/testsuite/gcc.target/powerpc/vec-minmax-1.c
new file mode 100644
index 00000000000..547798fd65c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/vec-minmax-1.c
@@ -0,0 +1,53 @@
+/* { dg-do compile { target { powerpc*-*-* } } } */
+/* { dg-require-effective-target powerpc_p9vector_ok } */
+/* { dg-options "-O2 -mdejagnu-cpu=power9" } */
+/* { dg-final { scan-assembler-times {\mxvmaxdp\M} 1 } } */
+/* { dg-final { scan-assembler-times {\mxvmaxsp\M} 1 } } */
+/* { dg-final { scan-assembler-times {\mxvmindp\M} 1 } } */
+/* { dg-final { scan-assembler-times {\mxvminsp\M} 1 } } */
+
+/* This test verifies that float or double vec_min/max are bound to
+ xv[min|max][d|s]p instructions when fast-math is not set. */
+
+
+#include <altivec.h>
+
+#ifdef _BIG_ENDIAN
+ const int PREF_D = 0;
+#else
+ const int PREF_D = 1;
+#endif
+
+double vmaxd (double a, double b)
+{
+ vector double va = vec_promote (a, PREF_D);
+ vector double vb = vec_promote (b, PREF_D);
+ return vec_extract (vec_max (va, vb), PREF_D);
+}
+
+double vmind (double a, double b)
+{
+ vector double va = vec_promote (a, PREF_D);
+ vector double vb = vec_promote (b, PREF_D);
+ return vec_extract (vec_min (va, vb), PREF_D);
+}
+
+#ifdef _BIG_ENDIAN
+ const int PREF_F = 0;
+#else
+ const int PREF_F = 3;
+#endif
+
+float vmaxf (float a, float b)
+{
+ vector float va = vec_promote (a, PREF_F);
+ vector float vb = vec_promote (b, PREF_F);
+ return vec_extract (vec_max (va, vb), PREF_F);
+}
+
+float vminf (float a, float b)
+{
+ vector float va = vec_promote (a, PREF_F);
+ vector float vb = vec_promote (b, PREF_F);
+ return vec_extract (vec_min (va, vb), PREF_F);
+}
diff --git a/gcc/testsuite/gcc.target/powerpc/vec-minmax-2.c
b/gcc/testsuite/gcc.target/powerpc/vec-minmax-2.c
new file mode 100644
index 00000000000..4c6f4365830
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/vec-minmax-2.c
@@ -0,0 +1,51 @@
+/* { dg-do compile { target { powerpc*-*-* } } } */
+/* { dg-require-effective-target powerpc_p9vector_ok } */
+/* { dg-options "-O2 -mdejagnu-cpu=power9 -ffast-math" } */
+/* { dg-final { scan-assembler-times {\mxsmaxcdp\M} 2 } } */
+/* { dg-final { scan-assembler-times {\mxsmincdp\M} 2 } } */
+
+/* This test verifies that float or double vec_min/max can be converted
+ to scalar comparison when fast-math is set. */
+
+
+#include <altivec.h>
+
+#ifdef _BIG_ENDIAN
+ const int PREF_D = 0;
+#else
+ const int PREF_D = 1;
+#endif
+
+double vmaxd (double a, double b)
+{
+ vector double va = vec_promote (a, PREF_D);
+ vector double vb = vec_promote (b, PREF_D);
+ return vec_extract (vec_max (va, vb), PREF_D);
+}
+
+double vmind (double a, double b)
+{
+ vector double va = vec_promote (a, PREF_D);
+ vector double vb = vec_promote (b, PREF_D);
+ return vec_extract (vec_min (va, vb), PREF_D);
+}
+
+#ifdef _BIG_ENDIAN
+ const int PREF_F = 0;
+#else
+ const int PREF_F = 3;
+#endif
+
+float vmaxf (float a, float b)
+{
+ vector float va = vec_promote (a, PREF_F);
+ vector float vb = vec_promote (b, PREF_F);
+ return vec_extract (vec_max (va, vb), PREF_F);
+}
+
+float vminf (float a, float b)
+{
+ vector float va = vec_promote (a, PREF_F);
+ vector float vb = vec_promote (b, PREF_F);
+ return vec_extract (vec_min (va, vb), PREF_F);
+}
