x/tools/go/ssa: misrepresents the dynamic behavior of shift with signed rhs #51363
Description
Input:
package main
func foo(x int) { _ = 1 << x }
func main() { foo(-1) }
Output:
func foo(x int):
0: entry P:0 S:0
t0 = convert uint64 <- int (x) uint64
t1 = 1:int << t0 int
return
Actual runtime behavior:
$ go run bar.go
panic: runtime error: negative shift amount
This issue is very similar to #50949, with much of the same possible fixes.
/cc @timothy-king