cmd/compile/internal/amd64: simplify code generation for signed division
The same switch statement handles code generation for signed division of
words, double words and quad words. Rather than using multiple switch
statements to select the appropriate instructions, determine all of the
correctly sized operands up front, then use them as needed.
Updates #59089
Change-Id: I2b7567c8e0ecb9904c37607332538c95b0521dca
Reviewed-on: https://go-review.googlesource.com/c/go/+/482657
Run-TryBot: Joel Sing <joel@sing.id.au> Reviewed-by: Keith Randall <khr@google.com> Reviewed-by: Michael Knyszek <mknyszek@google.com> Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>