diff mbox series

[30/35] tcg: Eliminate duplicate env store operations

Message ID 20231107024842.7650-31-richard.henderson@linaro.org
State Accepted
Commit 3eaadaeb4ee9cc6a1267882b3e31c893cd99bb9e
Headers show
Series [01/35] accel/tcg: Move HMP info jit and info opcount code | expand

Commit Message

Richard Henderson Nov. 7, 2023, 2:48 a.m. UTC 
Notice when a constant is stored to the same location twice.

Reviewed-by: Song Gao <gaosong@loongson.cn>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/optimize.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)
diff mbox series

Patch

diff --git a/tcg/optimize.c b/tcg/optimize.c
index b32ef0be0f..a4fe9ee9bb 100644
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -2269,6 +2269,19 @@  static bool fold_tcg_st_memcopy(OptContext *ctx, TCGOp *op)
     src = arg_temp(op->args[0]);
     ofs = op->args[2];
     type = ctx->type;
+
+    /*
+     * Eliminate duplicate stores of a constant.
+     * This happens frequently when the target ISA zero-extends.
+     */
+    if (ts_is_const(src)) {
+        TCGTemp *prev = find_mem_copy_for(ctx, type, ofs);
+        if (src == prev) {
+            tcg_op_remove(ctx->tcg, op);
+            return true;
+        }
+    }
+
     last = ofs + tcg_type_size(type) - 1;
     remove_mem_copy_in(ctx, ofs, last);
     record_mem_copy(ctx, type, src, ofs, last);