[gcc/devel/omp/gcc-9] i386: Fix -mavx -mno-mavx2 ICE with VEC_COND_EXPR [PR93637]

[Tobias Burnus]

https://gcc.gnu.org/g:b7cbce7a174292adc7c9d6db81bba6922a591d69

commit b7cbce7a174292adc7c9d6db81bba6922a591d69
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Mon Feb 10 22:44:40 2020 +0100

    i386: Fix -mavx -mno-mavx2 ICE with VEC_COND_EXPR [PR93637]
    
    As mentioned in the PR, for -mavx -mno-avx2 the backend does support
    vcondv4div4df and vcondv8siv8sf optabs (while generally 32-byte vectors
    aren't much supported in that case, it is performed using
    vandps/vandnps/vorps).  The problem is that after the last generic vector
    lowering (where the VEC_COND_EXPR still compares two V4DF vectors and
    has two V4DI last operands and V4DI result and so is considered ok) fre4
    folds the condition into constant, at which point the middle-end during
    expansion will try vcond_mask_optab and fall back to trying to expand it
    as the constant vector < 0 vcondv4div4di, but neither of them is supported
    for -mavx -mno-avx2 and thus we ICE.
    
    So, the options I see is either what the following patch does, also support
    vcond_mask_v4div4di and vcond_mask_v4siv4si already for TARGET_AVX, or
    require for vcondv4div4df and vcondv8siv8sf TARGET_AVX2 rather than current
    TARGET_AVX.
    
    2020-02-10  Jakub Jelinek  <jakub@redhat.com>
    
    	PR target/93637
    	* config/i386/sse.md (VI_256_AVX2): New mode iterator.
    	(vcond_mask_<mode><sseintvecmodelower>): Use it instead of VI_256.
    	Change condition from TARGET_AVX2 to TARGET_AVX.
    
    	* gcc.target/i386/avx-pr93637.c: New test.

Diff:
---
 gcc/ChangeLog                               |  7 +++++++
 gcc/config/i386/sse.md                      | 16 +++++++++++-----
 gcc/testsuite/ChangeLog                     |  5 +++++
 gcc/testsuite/gcc.target/i386/avx-pr93637.c | 17 +++++++++++++++++
 4 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 72c8ee6..3409135 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,6 +1,13 @@
 2020-02-13  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2020-02-10  Jakub Jelinek  <jakub@redhat.com>
+
+	PR target/93637
+	* config/i386/sse.md (VI_256_AVX2): New mode iterator.
+	(vcond_mask_<mode><sseintvecmodelower>): Use it instead of VI_256.
+	Change condition from TARGET_AVX2 to TARGET_AVX.
+
 	2020-02-08  Uroš Bizjak  <ubizjak@gmail.com>
 		    Jakub Jelinek  <jakub@redhat.com>
 
diff --git a/gcc/config/i386/sse.md b/gcc/config/i386/sse.md
index 659cbff..c0fe0ee 100644
--- a/gcc/config/i386/sse.md
+++ b/gcc/config/i386/sse.md
@@ -3180,13 +3180,19 @@
 	  (match_operand:<avx512fmaskmode> 3 "register_operand")))]
   "TARGET_AVX512BW")
 
+;; As vcondv4div4df and vcondv8siv8sf are enabled already with TARGET_AVX,
+;; and their condition can be folded late into a constant, we need to
+;; support vcond_mask_v4div4di and vcond_mask_v8siv8si for TARGET_AVX.
+(define_mode_iterator VI_256_AVX2 [(V32QI "TARGET_AVX2") (V16HI "TARGET_AVX2")
+				   V8SI V4DI])
+
 (define_expand "vcond_mask_<mode><sseintvecmodelower>"
-  [(set (match_operand:VI_256 0 "register_operand")
-	(vec_merge:VI_256
-	  (match_operand:VI_256 1 "nonimmediate_operand")
-	  (match_operand:VI_256 2 "nonimm_or_0_operand")
+  [(set (match_operand:VI_256_AVX2 0 "register_operand")
+	(vec_merge:VI_256_AVX2
+	  (match_operand:VI_256_AVX2 1 "nonimmediate_operand")
+	  (match_operand:VI_256_AVX2 2 "nonimm_or_0_operand")
 	  (match_operand:<sseintvecmode> 3 "register_operand")))]
-  "TARGET_AVX2"
+  "TARGET_AVX"
 {
   ix86_expand_sse_movcc (operands[0], operands[3],
 			 operands[1], operands[2]);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index c7b8e6a..9ec4d50 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,6 +1,11 @@
 2020-02-13  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2020-02-10  Jakub Jelinek  <jakub@redhat.com>
+
+	PR target/93637
+	* gcc.target/i386/avx-pr93637.c: New test.
+
 	2020-02-08  Uroš Bizjak  <ubizjak@gmail.com>
 		    Jakub Jelinek  <jakub@redhat.com>
 
diff --git a/gcc/testsuite/gcc.target/i386/avx-pr93637.c b/gcc/testsuite/gcc.target/i386/avx-pr93637.c
new file mode 100644
index 0000000..9e7a0a7
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/avx-pr93637.c
@@ -0,0 +1,17 @@
+/* PR target/93637 */
+/* { dg-do compile } */
+/* { dg-options "-mavx -mno-avx2 -O3 --param sccvn-max-alias-queries-per-access=3" } */
+
+double
+foo (void)
+{
+  int i;
+  double r = 7.0;
+  double a[] = { 0.0, 0.0, -0.0, 0.0, 0.0, -0.0, 1.0, 0.0, 0.0, -0.0, 1.0, 0.0, 1.0, 1.0 };
+
+  for (i = 0; i < sizeof (a) / sizeof (a[0]); ++i)
+    if (a[i] == 0.0)
+      r = a[i];
+
+  return r;
+}