[gcc r14-5518] slp: Fix handling of IFN_CLZ/CTZ [PR112536]

[gcc r14-5518] slp: Fix handling of IFN_CLZ/CTZ [PR112536]

[Jakub Jelinek]

https://gcc.gnu.org/g:9f35d8cd767155e9c24f5ef0944168711d38bc6b

commit r14-5518-g9f35d8cd767155e9c24f5ef0944168711d38bc6b
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Thu Nov 16 08:32:24 2023 +0100

    slp: Fix handling of IFN_CLZ/CTZ [PR112536]
    
    We ICE on the following testcase now that IFN_C[LT]Z calls can have one or
    two arguments (where 2 mean it is well defined at zero).
    The following patch makes us create child node only for the first argument
    and compatible_calls_p ensures the other argument is the same, which
    at least according to the testcase seems sufficient because of vect
    patterns.
    
    2023-11-16  Jakub Jelinek  <jakub@redhat.com>
    
            PR tree-optimization/112536
            * tree-vect-slp.cc (arg0_map): New variable.
            (vect_get_operand_map): For IFN_CLZ or IFN_CTZ, return arg0_map.
    
            * gcc.dg/pr112536.c: New test.

Diff:
---
 gcc/testsuite/gcc.dg/pr112536.c | 58 +++++++++++++++++++++++++++++++++++++++++
 gcc/tree-vect-slp.cc            |  5 ++++
 2 files changed, 63 insertions(+)

diff --git a/gcc/testsuite/gcc.dg/pr112536.c b/gcc/testsuite/gcc.dg/pr112536.c
new file mode 100644
index 00000000000..633e1312063
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr112536.c
@@ -0,0 +1,58 @@
+/* PR tree-optimization/112536 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-ipa-icf" } */
+/* { dg-additional-options "-mlzcnt -mavx512cd -mavx512vl" { target { i?86-*-* x86_64-*-* } } } */
+/* { dg-final { scan-assembler-times "\tvplzcntd\t" 3 { target { i?86-*-* x86_64-*-* } } } } */
+
+unsigned a[12];
+
+void
+foo (void)
+{
+  int i = a[0];
+  int j = a[1];
+  int k = a[2];
+  int l = a[3];
+  int e = i ? __builtin_clz (i) : __SIZEOF_INT__ * __CHAR_BIT__;
+  int f = j ? __builtin_clz (j) : __SIZEOF_INT__ * __CHAR_BIT__;
+  int g = k ? __builtin_clz (k) : __SIZEOF_INT__ * __CHAR_BIT__;
+  int h = l ? __builtin_clz (l) : __SIZEOF_INT__ * __CHAR_BIT__;
+  a[0] = e;
+  a[1] = f;
+  a[2] = g;
+  a[3] = h;
+}
+
+void
+bar (void)
+{
+  int i = a[4];
+  int j = a[5];
+  int k = a[6];
+  int l = a[7];
+  int e = i ? __builtin_clz (i) : __SIZEOF_INT__ * __CHAR_BIT__;
+  int f = __builtin_clz (j);
+  int g = __builtin_clz (k);
+  int h = l ? __builtin_clz (l) : __SIZEOF_INT__ * __CHAR_BIT__;
+  a[4] = e;
+  a[5] = f;
+  a[6] = g;
+  a[7] = h;
+}
+
+void
+baz (void)
+{
+  int i = a[8];
+  int j = a[9];
+  int k = a[10];
+  int l = a[11];
+  int e = __builtin_clz (i);
+  int f = j ? __builtin_clz (j) : __SIZEOF_INT__ * __CHAR_BIT__;
+  int g = __builtin_clz (k);
+  int h = l ? __builtin_clz (l) : __SIZEOF_INT__ * __CHAR_BIT__;
+  a[8] = e;
+  a[9] = f;
+  a[10] = g;
+  a[11] = h;
+}
diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index 33c4d1308f6..4a09b3c2aca 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -505,6 +505,7 @@ static const int cond_expr_maps[3][5] = {
   { 4, -2, -1, 1, 2 },
   { 4, -1, -2, 2, 1 }
 };
+static const int arg0_map[] = { 1, 0 };
 static const int arg1_map[] = { 1, 1 };
 static const int arg2_map[] = { 1, 2 };
 static const int arg1_arg4_map[] = { 2, 1, 4 };
@@ -580,6 +581,10 @@ vect_get_operand_map (const gimple *stmt, bool gather_scatter_p = false,
 		return nullptr;
 	    }
 
+	  case IFN_CLZ:
+	  case IFN_CTZ:
+	    return arg0_map;
+
 	  default:
 	    break;
 	  }