harec

commit cffdad98039c202e0c2e39bbf952dfdf6b26f0ab
parent 3520ab2c1510f12b066ab1d1dafcdba6abf2435b
Author: Drew DeVault <sir@cmpwn.com>
Date:   Thu,  5 Aug 2021 09:48:09 +0200

gen: commoditize branch consolidation

Signed-off-by: Drew DeVault <sir@cmpwn.com>

Diffstat:
M
include/gen.h
 | 
2
++
M
src/gen.c
 | 
16
++++------------
M
src/genutil.c
 | 
17
+++++++++++++++++

3 files changed, 23 insertions(+), 12 deletions(-)
diff --git a/include/gen.h b/include/gen.h
@@ -74,6 +74,8 @@ struct qbe_value mkqtmp(struct gen_context *ctx,
 struct qbe_value mkrtfunc(struct gen_context *ctx, const char *name);
 struct qbe_value mklabel(struct gen_context *ctx,
 	struct qbe_statement *stmt, const char *fmt);
+void branch_copyresult(struct gen_context *ctx, struct gen_value result,
+	struct gen_value merged, struct gen_value *out);
 
 // qinstr.c
 enum qbe_instr alloc_for_align(size_t align);
diff --git a/src/gen.c b/src/gen.c
@@ -537,10 +537,8 @@ gen_expr_if_with(struct gen_context *ctx,
 	struct gen_value *out)
 {
 	struct gen_value gvout = gv_void;
-	struct qbe_value qvout;
 	if (!out && type_dealias(expr->result)->storage != STORAGE_VOID) {
 		gvout = mktemp(ctx, expr->result, ".%d");
-		qvout = mkqval(ctx, &gvout);
 	}
 
 	struct qbe_statement ltrue, lfalse, lend;
@@ -553,20 +551,14 @@ gen_expr_if_with(struct gen_context *ctx,
 
 	push(&ctx->current->body, &ltrue);
 	struct gen_value vtrue = gen_expr_with(ctx, expr->_if.true_branch, out);
-	if (!out && type_dealias(expr->result)->storage != STORAGE_VOID) {
-		struct qbe_value qvtrue = mkqval(ctx, &vtrue);
-		pushi(ctx->current, &qvout, Q_COPY, &qvtrue, NULL);
-	}
+	branch_copyresult(ctx, vtrue, gvout, out);
 	pushi(ctx->current, NULL, Q_JMP, &bend, NULL);
 
 	push(&ctx->current->body, &lfalse);
 	if (expr->_if.false_branch) {
-		struct gen_value vfalse = gen_expr_with(
-			ctx, expr->_if.false_branch, out);
-		if (!out && type_dealias(expr->result)->storage != STORAGE_VOID) {
-			struct qbe_value qvfalse = mkqval(ctx, &vfalse);
-			pushi(ctx->current, &qvout, Q_COPY, &qvfalse, NULL);
-		}
+		struct gen_value vfalse = gen_expr_with(ctx,
+				expr->_if.false_branch, out);
+		branch_copyresult(ctx, vfalse, gvout, out);
 	}
 
 	push(&ctx->current->body, &lend);
diff --git a/src/genutil.c b/src/genutil.c
@@ -92,3 +92,20 @@ mklabel(struct gen_context *ctx, struct qbe_statement *stmt, const char *fmt)
 	val.name = strdup(genl(stmt, &ctx->id, fmt));
 	return val;
 }
+
+void
+branch_copyresult(struct gen_context *ctx,
+	struct gen_value result,
+	struct gen_value merged,
+	struct gen_value *out)
+{
+	// Branching expressions written in the _with style may need to
+	// consolodate each branch's result into a single temporary to return to
+	// the caller. This function facilitates that.
+	if (out || type_dealias(result.type)->storage == STORAGE_VOID) {
+		return;
+	}
+	struct qbe_value qmerged = mkqval(ctx, &merged);
+	struct qbe_value qval = mkqval(ctx, &result);
+	pushi(ctx->current, &qmerged, Q_COPY, &qval, NULL);
+}