amdgcn: Disallow unsupported permute on RDNA devices

The RDNA architecture has limited support for permute operations.  This should
allow use of the permutations that do work, and fall back to linear code for
other cases.

gcc/ChangeLog:

	* config/gcn/gcn-valu.md
	(vec_extract<V_MOV:mode><V_MOV_ALT:mode>): Add conditions for RDNA.
	* config/gcn/gcn.cc (gcn_vectorize_vec_perm_const): Check permutation
	details are supported on RDNA devices.

diff --git a/gcc/config/gcn/gcn-valu.md b/gcc/config/gcn/gcn-valu.md
index 23b441f8e8b6ae23c31fd281bd17a285aeb0b1ca..59e27d0aed790eadb39cd0673658206b5e85562e 100644 (file)
--- a/gcc/config/gcn/gcn-valu.md
+++ b/gcc/config/gcn/gcn-valu.md
@@ -982,7 +982,8 @@
    (match_operand:V_MOV 1 "register_operand")
    (match_operand 2 "immediate_operand")]
   "MODE_VF (<V_MOV_ALT:MODE>mode) < MODE_VF (<V_MOV:MODE>mode)
-   && <V_MOV_ALT:SCALAR_MODE>mode == <V_MOV:SCALAR_MODE>mode"
+   && <V_MOV_ALT:SCALAR_MODE>mode == <V_MOV:SCALAR_MODE>mode
+   && (!TARGET_RDNA2_PLUS || MODE_VF (<V_MOV:MODE>mode) <= 32)"
   {
     int numlanes = GET_MODE_NUNITS (<V_MOV_ALT:MODE>mode);
     int firstlane = INTVAL (operands[2]) * numlanes;

diff --git a/gcc/config/gcn/gcn.cc b/gcc/config/gcn/gcn.cc
index 20be45565462b6d399de8e9444682dd7a74c8790..4559d6932d4a0c5a6dd42df0afcc9c13dad8e478 100644 (file)
--- a/gcc/config/gcn/gcn.cc
+++ b/gcc/config/gcn/gcn.cc
@@ -5110,19 +5110,24 @@ gcn_vectorize_vec_perm_const (machine_mode vmode, machine_mode op_mode,
   gcc_assert (nelt <= 64);
   gcc_assert (sel.length () == nelt);
 
-  if (!dst)
-    {
-      /* All vector permutations are possible on this architecture,
-         with varying degrees of efficiency depending on the permutation. */
-      return true;
-    }
-
   unsigned int perm[64];
   for (unsigned int i = 0; i < nelt; ++i)
     perm[i] = sel[i] & (2 * nelt - 1);
   for (unsigned int i = nelt; i < 64; ++i)
     perm[i] = 0;
 
+  /* RDNA devices can only do permutations within each group of 32-lanes.
+     Reject permutations that cross the boundary.  */
+  if (TARGET_RDNA2_PLUS)
+    for (unsigned int i = 0; i < nelt; i++)
+      if (i < 31 ? perm[i] > 31 : perm[i] < 32)
+       return false;
+
+  /* All vector permutations are possible on other architectures,
+     with varying degrees of efficiency depending on the permutation. */
+  if (!dst)
+    return true;
+
   src0 = force_reg (vmode, src0);
   src1 = force_reg (vmode, src1);