shithub: riscv

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ref: 766a641d252cf4de21d50b2753dd8c25490b8ba0
parent: d1204d9b8085634241bf5655279e54a606406cb1
author: cinap_lenrek <cinap_lenrek@felloff.net>
date: Fri Sep 6 22:11:18 EDT 2019

cc: fix void cast crash

the following code reproduces the crash:

void
foo(void)
{
}

void
main(int argc, char **argv)
{
	(void)(1 ? (void)0 : foo());
}

the problem is that side() gives a false positive on the OCOND
with later constant folding eleminating the acutal side effect
and OCAST ending up with two nested OCATS with the nested one
being zapped (type == T).

--- a/sys/src/cmd/cc/com.c

+++ b/sys/src/cmd/cc/com.c

@@ -1081,6 +1081,11 @@

 		if(castucom(n))

 			warn(n, "32-bit unsigned complement zero-extended to 64 bits");

 		ccom(l);

+		if(l->type == T){

+			n->left = Z;

+			n->type = T;

+			break;

+		}

 		if(l->op == OCONST) {

 			evconst(n);

 			if(n->op == OCONST)