cmd/compile: teach prove about and operation

For this code:
z &= 63
_ = x<<z | x>>(64-z)
Now can prove 'x<<z' in bound. In ppc64 lowering pass, it will not
produce an extra '(ANDconst <typ.Int64> [63] z)' causing
codegen/rotate.go failed. Just remove the type check in rewrite rules
as the workaround.

Removes 32 bounds checks during make.bat.

Fixes #52563.

Change-Id: I14ed2c093ff5638dfea7de9bc7649c0f756dd71a
Reviewed-on: https://go-review.googlesource.com/c/go/+/404315
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: David Chase <drchase@google.com>
Auto-Submit: Keith Randall <khr@golang.org>
Run-TryBot: Wayne Zuo <wdvxdr@golangcn.org>
TryBot-Result: Gopher Robot <gobot@golang.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/test/prove.go b/test/prove.go
index 83b0380838..b7cc511f53 100644
--- a/test/prove.go
+++ b/test/prove.go
@@ -1036,6 +1036,14 @@ func divShiftClean32(n int32) int32 {
 	return n / int32(16) // ERROR "Proved Rsh32x64 shifts to zero"
 }
 
+func and(p []byte) ([]byte, []byte) { // issue #52563
+	const blocksize = 16
+	fullBlocks := len(p) &^ (blocksize - 1)
+	blk := p[:fullBlocks] // ERROR "Proved IsSliceInBounds$"
+	rem := p[fullBlocks:] // ERROR "Proved IsSliceInBounds$"
+	return blk, rem
+}
+
 //go:noinline
 func useInt(a int) {
 }