__builtin_expect

goplus · Jul 21, 2022 · aab7a91 · aab7a91
1 parent b32fb1c
commit aab7a91
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Showing 3 changed files with 19 additions and 0 deletions.
diff --git a/cl/codebuild.go b/cl/codebuild.go
@@ -429,6 +429,10 @@ func binaryOp(ctx *blockCtx, op token.Token, v *cast.Node) {
 	adjustIntConst(ctx, ret, ret.Type)
 }
 
+func compareOp(ctx *blockCtx, op token.Token, src ast.Node) {
+	ctx.cb.BinaryOp(op, src)
+}
+
 func untypedZeroToNil(v *gox.Element) {
 	v.Type = types.Typ[types.UntypedNil]
 	v.Val = &ast.Ident{Name: "nil"}

diff --git a/cl/expr.go b/cl/expr.go
@@ -272,6 +272,11 @@ func compileCallExpr(ctx *blockCtx, v *ast.Node) {
 				compileExpr(ctx, v.Inner[2])
 				cb.Assign(1)
 				return
+			case "__builtin_expect":
+				compileExpr(ctx, v.Inner[1])
+				compileExpr(ctx, v.Inner[2])
+				compareOp(ctx, token.EQL, ctx.goNode(v))
+				return
 			}
 		}
 		for i := 0; i < n; i++ {

diff --git a/testdata/operator/operator.c b/testdata/operator/operator.c
@@ -1,6 +1,9 @@
 #include <stdio.h>
 #include <string.h>
 
+#define likely(x) __builtin_expect(!!(x), 1)
+#define unlikely(x) __builtin_expect(!!(x), 0)
+
 void f() {
 	double a;
 	float b;
@@ -14,6 +17,12 @@ int g(int ret) {
     return ret;
 }
 
+void test() {
+    if (likely(g(100))) {
+        printf("likely(g(100))\n");
+    }
+}
+
 void h() {
     g(1) || g(0);
     g(0) || g(1);
@@ -44,5 +53,6 @@ int main() {
     pfoo->msg[2] = '!', printf("%s\n", foo.msg);
     h();
     printf("%d\n", (int)((-0x2000ULL << (8*sizeof(long)-1)) | (4096ULL -1)));
+    test();
     return 0;
 }