cmd/compile/internal/ssa: prove support induction variable pair

We have two induction variables i and j in the following loop:

for i, j := 0, len(s)-1; i < j; i, j = i+1, j-1 {
    // loop body
}

This CL enables the prove pass to handle cases where one if block
uses two induction variables.

Updates #45078

Change-Id: I8b8dc8b7b2d160a796dab1d1e29a00ef4e8e8157
Reviewed-on: https://go-review.googlesource.com/c/go/+/757700
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

0 files changed, 0 insertions, 0 deletions