commit 3f2b1f8376c11327ca2ea54cdc1085d4d4c1d97c
author Richard Henderson <richard.henderson@linaro.org> Thu Aug 26 13:08:54 2021 -0700
committer Richard Henderson <richard.henderson@linaro.org> Thu Oct 28 20:55:07 2021 -0700
tree 6a9a946e64cc4c95b87ed68675d7de108648cb12
parent 57fe5c6df21c05af11435b2ed426a42ee3345298

tcg/optimize: Propagate sign info for logical operations

Sign repetitions are perforce all identical, whether they are 1 or 0.
Bitwise operations preserve the relative quantity of the repetitions.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

tcg/optimize.c

diff --git a/tcg/optimize.c b/tcg/optimize.c
index ef202ab..de1abd9 100644
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -968,6 +968,13 @@
     ctx->z_mask = z1 & z2;
 
     /*
+     * Sign repetitions are perforce all identical, whether they are 1 or 0.
+     * Bitwise operations preserve the relative quantity of the repetitions.
+     */
+    ctx->s_mask = arg_info(op->args[1])->s_mask
+                & arg_info(op->args[2])->s_mask;
+
+    /*
      * Known-zeros does not imply known-ones.  Therefore unless
      * arg2 is constant, we can't infer affected bits from it.
      */
@@ -1002,6 +1009,8 @@
     }
     ctx->z_mask = z1;
 
+    ctx->s_mask = arg_info(op->args[1])->s_mask
+                & arg_info(op->args[2])->s_mask;
     return fold_masks(ctx, op);
 }
 
@@ -1300,6 +1309,9 @@
         fold_xi_to_not(ctx, op, 0)) {
         return true;
     }
+
+    ctx->s_mask = arg_info(op->args[1])->s_mask
+                & arg_info(op->args[2])->s_mask;
     return false;
 }
 
@@ -1487,6 +1499,8 @@
 
     ctx->z_mask = arg_info(op->args[3])->z_mask
                 | arg_info(op->args[4])->z_mask;
+    ctx->s_mask = arg_info(op->args[3])->s_mask
+                & arg_info(op->args[4])->s_mask;
 
     if (arg_is_const(op->args[3]) && arg_is_const(op->args[4])) {
         uint64_t tv = arg_info(op->args[3])->val;
@@ -1585,6 +1599,9 @@
         fold_xi_to_not(ctx, op, -1)) {
         return true;
     }
+
+    ctx->s_mask = arg_info(op->args[1])->s_mask
+                & arg_info(op->args[2])->s_mask;
     return false;
 }
 
@@ -1614,6 +1631,9 @@
         fold_xi_to_not(ctx, op, 0)) {
         return true;
     }
+
+    ctx->s_mask = arg_info(op->args[1])->s_mask
+                & arg_info(op->args[2])->s_mask;
     return false;
 }
 
@@ -1623,6 +1643,8 @@
         return true;
     }
 
+    ctx->s_mask = arg_info(op->args[1])->s_mask;
+
     /* Because of fold_to_not, we want to always return true, via finish. */
     finish_folding(ctx, op);
     return true;
@@ -1638,6 +1660,8 @@
 
     ctx->z_mask = arg_info(op->args[1])->z_mask
                 | arg_info(op->args[2])->z_mask;
+    ctx->s_mask = arg_info(op->args[1])->s_mask
+                & arg_info(op->args[2])->s_mask;
     return fold_masks(ctx, op);
 }
 
@@ -1649,6 +1673,9 @@
         fold_ix_to_not(ctx, op, 0)) {
         return true;
     }
+
+    ctx->s_mask = arg_info(op->args[1])->s_mask
+                & arg_info(op->args[2])->s_mask;
     return false;
 }
 
@@ -1922,6 +1949,8 @@
 
     ctx->z_mask = arg_info(op->args[1])->z_mask
                 | arg_info(op->args[2])->z_mask;
+    ctx->s_mask = arg_info(op->args[1])->s_mask
+                & arg_info(op->args[2])->s_mask;
     return fold_masks(ctx, op);
 }