tree-optimization/112623 - forwprop VEC_PACK_TRUNC generation

Message ID 20231121143529.5B1003858C30@sourceware.org
State Accepted
Headers
Series tree-optimization/112623 - forwprop VEC_PACK_TRUNC generation |

Checks

Context Check Description
snail/gcc-patch-check success Github commit url

Commit Message

Richard Biener Nov. 21, 2023, 2:35 p.m. UTC
  For vec_pack_trunc patterns there can be an ambiguity for the
source mode for BFmode vs HFmode.  The vectorizer checks
the insns operand mode for this, the following makes forwprop
do the same.  That of course doesn't help if the target supports
both conversions.

Bootstrapped and tested on x86_64-unknown-linux-gnu, OK?

Thanks,
Richard.

	PR tree-optimization/112623
	* tree-ssa-forwprop.cc (simplify_vector_constructor):
	Check the source mode of the insn for vector pack/unpacks.

	* gcc.target/i386/pr112623.c: New testcase.
---
 gcc/testsuite/gcc.target/i386/pr112623.c | 11 +++++++++++
 gcc/tree-ssa-forwprop.cc                 | 13 +++++++++----
 2 files changed, 20 insertions(+), 4 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr112623.c
  

Patch

diff --git a/gcc/testsuite/gcc.target/i386/pr112623.c b/gcc/testsuite/gcc.target/i386/pr112623.c
new file mode 100644
index 00000000000..c4ebacec85c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr112623.c
@@ -0,0 +1,11 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O -mavx512vl -mavx512fp16" } */
+
+typedef __bf16 __attribute__((__vector_size__ (16))) BF;
+typedef float __attribute__((__vector_size__ (32))) F;
+
+BF
+foo (F f)
+{
+  return __builtin_convertvector (f, BF);
+}
diff --git a/gcc/tree-ssa-forwprop.cc b/gcc/tree-ssa-forwprop.cc
index d39dfc1065f..0fb21e58138 100644
--- a/gcc/tree-ssa-forwprop.cc
+++ b/gcc/tree-ssa-forwprop.cc
@@ -47,6 +47,8 @@  along with GCC; see the file COPYING3.  If not see
 #include "tree-cfgcleanup.h"
 #include "cfganal.h"
 #include "optabs-tree.h"
+#include "insn-config.h"
+#include "recog.h"
 #include "tree-vector-builder.h"
 #include "vec-perm-indices.h"
 #include "internal-fn.h"
@@ -2978,6 +2980,7 @@  simplify_vector_constructor (gimple_stmt_iterator *gsi)
 	  /* Only few targets implement direct conversion patterns so try
 	     some simple special cases via VEC_[UN]PACK[_FLOAT]_LO_EXPR.  */
 	  optab optab;
+	  insn_code icode;
 	  tree halfvectype, dblvectype;
 	  enum tree_code unpack_op;
 
@@ -3015,8 +3018,9 @@  simplify_vector_constructor (gimple_stmt_iterator *gsi)
 	      && (optab = optab_for_tree_code (unpack_op,
 					       dblvectype,
 					       optab_default))
-	      && (optab_handler (optab, TYPE_MODE (dblvectype))
-		  != CODE_FOR_nothing))
+	      && ((icode = optab_handler (optab, TYPE_MODE (dblvectype)))
+		  != CODE_FOR_nothing)
+	      && (insn_data[icode].operand[0].mode == TYPE_MODE (type)))
 	    {
 	      gimple_seq stmts = NULL;
 	      tree dbl;
@@ -3054,8 +3058,9 @@  simplify_vector_constructor (gimple_stmt_iterator *gsi)
 		   && (optab = optab_for_tree_code (VEC_PACK_TRUNC_EXPR,
 						    halfvectype,
 						    optab_default))
-		   && (optab_handler (optab, TYPE_MODE (halfvectype))
-		       != CODE_FOR_nothing))
+		   && ((icode = optab_handler (optab, TYPE_MODE (halfvectype)))
+		       != CODE_FOR_nothing)
+		   && (insn_data[icode].operand[0].mode == TYPE_MODE (type)))
 	    {
 	      gimple_seq stmts = NULL;
 	      tree low = gimple_build (&stmts, BIT_FIELD_REF, halfvectype,