r600/sb: cleanup if_conversion iterator to be legal C++

The current code causes:
/usr/include/c++/8/debug/safe_iterator.h:207:
Error: attempt to copy from a singular iterator.

This is due to the iterators getting invalidated, fix the
reverse iterator to use the return value from erase, and
cast it properly.

(used Mathias suggestion)
Cc: <[email protected]>
Reviewed-by: Mathias Fröhlich <[email protected]>

1 files changed, 4 insertions, 7 deletions

diff --git a/src/gallium/drivers/r600/sb/sb_if_conversion.cpp b/src/gallium/drivers/r600/sb/sb_if_conversion.cpp
index 3f6431b80f5..017153434fc 100644
--- a/src/gallium/drivers/r600/sb/sb_if_conversion.cpp
+++ b/src/gallium/drivers/r600/sb/sb_if_conversion.cpp
@@ -42,16 +42,13 @@ int if_conversion::run() {
 	regions_vec &rv = sh.get_regions();
 
 	unsigned converted = 0;
-
-	for (regions_vec::reverse_iterator N, I = rv.rbegin(), E = rv.rend();
-			I != E; I = N) {
-		N = I; ++N;
-
+	for (regions_vec::reverse_iterator I = rv.rbegin(); I != rv.rend(); ) {
 		region_node *r = *I;
 		if (run_on(r)) {
-			rv.erase(I.base() - 1);
+			I = regions_vec::reverse_iterator(rv.erase((++I).base()));
 			++converted;
-		}
+		} else
+			++I;
 	}
 	return 0;
 }