shithub: scc

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ref: 56338bb08045561cdc17b33c9e9f4e5721807778
parent: a926e8f5971ee8598fc7083ad9911da0c23fc76d
author: Roberto E. Vargas Caballero <k0ga@shike2.com>
date: Wed Nov 17 05:43:58 EST 2021 

cc1: Fix validation of folded multiplication

The code was negating the minimum of the type but that
value was already negative in the case of integer and
float expressions.


--- a/src/cmd/cc/cc1/fold.c
+++ b/src/cmd/cc/cc1/fold.c
@@ -15,7 +15,7 @@
 addi(TINT l, TINT r, Type *tp)
 {
 	struct limits *lim = getlimits(tp);
-	TINT max = lim->max.i, min = -lim->min.i;
+	TINT max = lim->max.i, min = lim->min.i;
 
 	if (l < 0 && r < 0 && l >= min - r ||
 	    l == 0 ||
@@ -63,7 +63,7 @@
 muli(TINT l, TINT r, Type *tp)
 {
 	struct limits *lim = getlimits(tp);
-	TINT max = lim->max.i, min = -lim->min.i;
+	TINT max = lim->max.i, min = lim->min.i;
 
 	if (l > -1 && l <= 1 ||
 	    r > -1 && r <= 1 ||