[COMMITTED 5/7] Add relation effects between operands to MINUS_EXPR.
Tue Jun 22 13:18:48 GMT 2021
This patch enhances processing of OP_MINUS to show how we can utilize
relations between op1 and op2 to produce a better result. Given:
a_3 = b_4 - d_1
if we know b_4 > d_1, on top of whatever other range calculations we can
do with the actual ranges, we can apply the knowledge that the result
must also be in the range [1, +INF] as well.
likewise, if we know b_4 == d_1, we know the result is [0,0]
This provide a sample of how applying a relation between 2 operands is
Bootstraps on x86_64-pc-linux-gnu with no regressions. Pushed.
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