From 37e0df8a9be5a8232f4ccb73cdadb02121ba523f Mon Sep 17 00:00:00 2001 From: Jiufu Guo Date: Tue, 10 Mar 2020 13:51:57 +0800 Subject: [PATCH] rs6000: Check -+0 and NaN for smax/smin generation PR93709 mentioned regressions on maxlocval_4.f90 and minlocval_f.f90 which relates to max of '-inf' and 'nan'. This regression occur on P9 because P9 new instruction 'xsmaxcdp' is generated. And for C code `a < b ? b : a` is also generated as `xsmaxcdp` under -O2 for P9. While this instruction behavior more like C/C++ semantic (a>b?a:b). This generates prevents 'xsmaxcdp' to be generated for those cases. 'xsmincdp' also is handled in patch. gcc/ 2020-03-10 Jiufu Guo PR target/93709 * gcc/config/rs6000/rs6000.c (rs6000_emit_p9_fp_minmax): Check NAN and SIGNED_ZEROR for smax/smin. gcc/testsuite 2020-03-10 Jiufu Guo PR target/93709 * gcc.target/powerpc/p9-minmax-3.c: New test. --- gcc/ChangeLog | 6 ++++++ gcc/config/rs6000/rs6000.c | 6 +++++- gcc/testsuite/ChangeLog | 5 +++++ gcc/testsuite/gcc.target/powerpc/p9-minmax-3.c | 17 +++++++++++++++++ 4 files changed, 33 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/gcc.target/powerpc/p9-minmax-3.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index c5256616408..5b67b79745f 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2020-03-10 Jiufu Guo + + PR target/93709 + * gcc/config/rs6000/rs6000.c (rs6000_emit_p9_fp_minmax): Check + NAN and SIGNED_ZEROR for smax/smin. + 2020-03-10 Will Schmidt PR target/90763 diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c index 848a4ef451e..46b7dec2abd 100644 --- a/gcc/config/rs6000/rs6000.c +++ b/gcc/config/rs6000/rs6000.c @@ -14831,7 +14831,11 @@ rs6000_emit_p9_fp_minmax (rtx dest, rtx op, rtx true_cond, rtx false_cond) if (rtx_equal_p (op0, true_cond) && rtx_equal_p (op1, false_cond)) ; - else if (rtx_equal_p (op1, true_cond) && rtx_equal_p (op0, false_cond)) + /* Only when NaNs and signed-zeros are not in effect, smax could be + used for `op0 < op1 ? op1 : op0`, and smin could be used for + `op0 > op1 ? op1 : op0`. */ + else if (rtx_equal_p (op1, true_cond) && rtx_equal_p (op0, false_cond) + && !HONOR_NANS (compare_mode) && !HONOR_SIGNED_ZEROS (compare_mode)) max_p = !max_p; else diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index da525a38cf1..c76d891a3e6 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2020-03-10 Jiufu Guo + + PR target/93709 + * gcc.target/powerpc/p9-minmax-3.c: New test. + 2020-03-10 Will Schmidt PR target/90763 diff --git a/gcc/testsuite/gcc.target/powerpc/p9-minmax-3.c b/gcc/testsuite/gcc.target/powerpc/p9-minmax-3.c new file mode 100644 index 00000000000..141603e05b4 --- /dev/null +++ b/gcc/testsuite/gcc.target/powerpc/p9-minmax-3.c @@ -0,0 +1,17 @@ +/* { dg-do compile { target { powerpc*-*-* } } } */ +/* { dg-require-effective-target powerpc_p9vector_ok } */ +/* { dg-options "-mdejagnu-cpu=power9 -O2 -mpower9-minmax" } */ +/* { dg-final { scan-assembler-not "xsmaxcdp" } } */ +/* { dg-final { scan-assembler-not "xsmincdp" } } */ + +double +dbl_max1 (double a, double b) +{ + return a < b ? b : a; +} + +double +dbl_min1 (double a, double b) +{ + return a > b ? b : a; +} -- 2.30.2