[PATCH] middle-end/113576 - zero padding of vector bools when expanding compares

[Richard Biener]

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.

Bootstrapped and tested on x86_64-unknown-linux-gnu.

OK?

Thanks,
Richard.

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

diff --git a/gcc/dojump.cc b/gcc/dojump.cc
index e2d2b3cb111..ec2a365e488 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 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 fc5e998e329..096081fdc53 100644
--- a/gcc/expr.cc
+++ b/gcc/expr.cc
@@ -13502,6 +13502,7 @@ 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;
@@ -13694,6 +13695,22 @@ 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 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);
 
-- 
2.35.3