[PATCH v1 37/51] perf expr: More explicit NAN handling

[Ian Rogers]

Comparison and logical operations on NAN won't ensure the result is
NAN. Ensure NANs are propogated so that threshold expressions like
"tma_fetch_latency > 0.1 & tma_frontend_bound > 0.15" don't yield a
number when the components are NAN.

Signed-off-by: Ian Rogers <irogers at google.com>
---
 tools/perf/util/expr.y | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/expr.y b/tools/perf/util/expr.y
index 635e562350c5..250e444bf032 100644
--- a/tools/perf/util/expr.y
+++ b/tools/perf/util/expr.y
@@ -127,7 +127,11 @@ static struct ids handle_id(struct expr_parse_ctx *ctx, char *id,
 	if (!compute_ids || (is_const(LHS.val) && is_const(RHS.val))) { \
 		assert(LHS.ids == NULL);				\
 		assert(RHS.ids == NULL);				\
-		RESULT.val = (long)LHS.val OP (long)RHS.val;		\
+		if (isnan(LHS.val) || isnan(RHS.val)) {			\
+			RESULT.val = NAN;				\
+		} else {						\
+			RESULT.val = (long)LHS.val OP (long)RHS.val;	\
+		}							\
 		RESULT.ids = NULL;					\
 	} else {							\
 	        RESULT = union_expr(LHS, RHS);				\
@@ -137,7 +141,11 @@ static struct ids handle_id(struct expr_parse_ctx *ctx, char *id,
 	if (!compute_ids || (is_const(LHS.val) && is_const(RHS.val))) { \
 		assert(LHS.ids == NULL);				\
 		assert(RHS.ids == NULL);				\
-		RESULT.val = LHS.val OP RHS.val;			\
+		if (isnan(LHS.val) || isnan(RHS.val)) {			\
+			RESULT.val = NAN;				\
+		} else {						\
+			RESULT.val = LHS.val OP RHS.val;		\
+		}							\
 		RESULT.ids = NULL;					\
 	} else {							\
 	        RESULT = union_expr(LHS, RHS);				\
-- 
2.39.2.637.g21b0678d19-goog