[gcc r14-8975] middle-end/113576 - zero padding of vector bools when expanding compares

[gcc r14-8975] middle-end/113576 - zero padding of vector bools when expanding compares

[Richard Biener]

https://gcc.gnu.org/g:5352ede92483b949e811cbdcdfaec5378f3e06d6

commit r14-8975-g5352ede92483b949e811cbdcdfaec5378f3e06d6
Author: Richard Biener <rguenther@suse.de>
Date:   Fri Feb 9 08:15:44 2024 +0100

    middle-end/113576 - zero padding of vector bools when expanding compares
    
    The following zeros paddings of vector bools when expanding compares
    and the mode used for the compare is an integer mode.  In that case
    targets cannot distinguish between a 4 element and 8 element vector
    compare (both get to the QImode compare optab) so we have to do the
    job in the middle-end.
    
            PR middle-end/113576
            * expr.cc (do_store_flag): For vector bool compares of vectors
            with padding zero that.
            * dojump.cc (do_compare_and_jump): Likewise.

Diff:
---
 gcc/dojump.cc | 16 ++++++++++++++++
 gcc/expr.cc   | 17 +++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/gcc/dojump.cc b/gcc/dojump.cc
index e2d2b3cb111e..ac744e54cf89 100644
--- a/gcc/dojump.cc
+++ b/gcc/dojump.cc
@@ -1266,6 +1266,7 @@ do_compare_and_jump (tree treeop0, tree treeop1, enum rtx_code signed_code,
   machine_mode mode;
   int unsignedp;
   enum rtx_code code;
+  unsigned HOST_WIDE_INT nunits;
 
   /* Don't crash if the comparison was erroneous.  */
   op0 = expand_normal (treeop0);
@@ -1308,6 +1309,21 @@ do_compare_and_jump (tree treeop0, tree treeop1, enum rtx_code signed_code,
       emit_insn (targetm.gen_canonicalize_funcptr_for_compare (new_op1, op1));
       op1 = new_op1;
     }
+  /* For boolean vectors with less than mode precision
+     make sure to fill padding with consistent values.  */
+  else if (VECTOR_BOOLEAN_TYPE_P (type)
+	   && SCALAR_INT_MODE_P (mode)
+	   && TYPE_VECTOR_SUBPARTS (type).is_constant (&nunits)
+	   && maybe_ne (GET_MODE_PRECISION (mode), nunits))
+    {
+      gcc_assert (code == EQ || code == NE);
+      op0 = expand_binop (mode, and_optab, op0,
+			  GEN_INT ((1 << nunits) - 1), NULL_RTX,
+			  true, OPTAB_WIDEN);
+      op1 = expand_binop (mode, and_optab, op1,
+			  GEN_INT ((1 << nunits) - 1), NULL_RTX,
+			  true, OPTAB_WIDEN);
+    }
 
   do_compare_rtx_and_jump (op0, op1, code, unsignedp, treeop0, mode,
 			   ((mode == BLKmode)
diff --git a/gcc/expr.cc b/gcc/expr.cc
index 444f04e10cf7..e238811110e4 100644
--- a/gcc/expr.cc
+++ b/gcc/expr.cc
@@ -13505,6 +13505,7 @@ do_store_flag (sepops ops, rtx target, machine_mode mode)
   rtx op0, op1;
   rtx subtarget = target;
   location_t loc = ops->location;
+  unsigned HOST_WIDE_INT nunits;
 
   arg0 = ops->op0;
   arg1 = ops->op1;
@@ -13697,6 +13698,22 @@ do_store_flag (sepops ops, rtx target, machine_mode mode)
 
   expand_operands (arg0, arg1, subtarget, &op0, &op1, EXPAND_NORMAL);
 
+  /* For boolean vectors with less than mode precision
+     make sure to fill padding with consistent values.  */
+  if (VECTOR_BOOLEAN_TYPE_P (type)
+      && SCALAR_INT_MODE_P (operand_mode)
+      && TYPE_VECTOR_SUBPARTS (type).is_constant (&nunits)
+      && maybe_ne (GET_MODE_PRECISION (operand_mode), nunits))
+    {
+      gcc_assert (code == EQ || code == NE);
+      op0 = expand_binop (mode, and_optab, op0,
+			  GEN_INT ((1 << nunits) - 1), NULL_RTX,
+			  true, OPTAB_WIDEN);
+      op1 = expand_binop (mode, and_optab, op1,
+			  GEN_INT ((1 << nunits) - 1), NULL_RTX,
+			  true, OPTAB_WIDEN);
+    }
+
   if (target == 0)
     target = gen_reg_rtx (mode);