From 571109481fa1f58b3f8bffb8d2bc81385b549b35 Mon Sep 17 00:00:00 2001
From: Stephen Williams <steve@icarus.com>
Date: Wed, 30 Sep 2015 12:35:19 -0700
Subject: [PATCH] Use cmpi in more cases

Before this patch, only literals on the right side of a < compare
(or left side of a > compare) would be blended into a %cmpi instruction.
This patch broadends the cases where the %cmpi can be used.
---
 tgt-vvp/eval_condit.c | 58 ++++++++++++++++++++++++++++++++++---------
 1 file changed, 46 insertions(+), 12 deletions(-)

diff --git a/tgt-vvp/eval_condit.c b/tgt-vvp/eval_condit.c
index d4cd104a6..59c7a88c6 100644
--- a/tgt-vvp/eval_condit.c
+++ b/tgt-vvp/eval_condit.c
@@ -189,21 +189,48 @@ static int draw_condition_binary_le(ivl_expr_t expr)
       char use_opcode = ivl_expr_opcode(expr);
       char s_flag = (ivl_expr_signed(le) && ivl_expr_signed(re)) ? 's' : 'u';
 
-	/* If this is a > or >=, then convert it to < or <= by
-	   swapping the operands. Adjust the opcode to match. */
-      switch (use_opcode) {
-	  case 'G':
+      if (test_immediate_vec4_ok(le) && !test_immediate_vec4_ok(re)) {
 	    tmp = le;
 	    le = re;
 	    re = tmp;
-	    use_opcode = 'L';
-	    break;
-	  case '>':
-	    tmp = le;
-	    le = re;
-	    re = tmp;
-	    use_opcode = '<';
-	    break;
+
+	    switch (use_opcode) {
+		case 'G':
+		  use_opcode = 'L';
+		  break;
+		case 'L':
+		  use_opcode = 'G';
+		  break;
+		case '>':
+		  use_opcode = '<';
+		  break;
+		case '<':
+		  use_opcode = '>';
+		  break;
+		default:
+		  assert(0);
+		  break;
+	    }
+
+      } else if (!test_immediate_vec4_ok(re)) {
+	      /* If this is a > or >=, then convert it to < or <= by
+		 swapping the operands. Adjust the opcode to match. Do
+		 this because the instruction really only supports <
+		 and <= and we can avoid a %flag_inv instruction. */
+	    switch (use_opcode) {
+		case 'G':
+		  tmp = le;
+		  le = re;
+		  re = tmp;
+		  use_opcode = 'L';
+		  break;
+		case '>':
+		  tmp = le;
+		  le = re;
+		  re = tmp;
+		  use_opcode = '<';
+		  break;
+	    }
       }
 
 	/* NOTE: I think I would rather the elaborator handle the
@@ -231,6 +258,13 @@ static int draw_condition_binary_le(ivl_expr_t expr)
       }
 
       switch (use_opcode) {
+	  case '>':
+	    fprintf(vvp_out, "    %%flag_or 5, 4; GT is !LE\n");
+	    fprintf(vvp_out, "    %%flag_inv 5;\n");
+	    return 5;
+	  case 'G':
+	    fprintf(vvp_out, "    %%flag_inv 5; GE is !LT\n");
+	    return 5;
 	  case '<':
 	    return 5;
 	  case 'L':