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 // Copyright 2016 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package ssa import "testing" // TestNlzNto tests nlz/nto of the same number which is used in some of // the rewrite rules. func TestNlzNto(t *testing.T) { // construct the bit pattern 000...111, nlz(x) + nto(0) = 64 var x int64 for i := int64(0); i < 64; i++ { if got := nto(x); got != i { t.Errorf("expected nto(0x%X) = %d, got %d", x, i, got) } if got := nlz(x); got != 64-i { t.Errorf("expected nlz(0x%X) = %d, got %d", x, 64-i, got) } x = (x << 1) | 1 } x = 0 // construct the bit pattern 000...111, with bit 33 set as well. for i := int64(0); i < 64; i++ { tx := x | (1 << 32) // nto should be the the number of bits we've shifted on, with an extra bit // at iter 32 ntoExp := i if ntoExp == 32 { ntoExp = 33 } if got := nto(tx); got != ntoExp { t.Errorf("expected nto(0x%X) = %d, got %d", tx, ntoExp, got) } // sinec bit 33 is set, nlz can be no greater than 31 nlzExp := 64 - i if nlzExp > 31 { nlzExp = 31 } if got := nlz(tx); got != nlzExp { t.Errorf("expected nlz(0x%X) = %d, got %d", tx, nlzExp, got) } x = (x << 1) | 1 } } func TestNlz(t *testing.T) { var nlzTests = []struct { v int64 exp int64 }{{0x00, 64}, {0x01, 63}, {0x0F, 60}, {0xFF, 56}, {0xffffFFFF, 32}, {-0x01, 0}} for _, tc := range nlzTests { if got := nlz(tc.v); got != tc.exp { t.Errorf("expected nlz(0x%X) = %d, got %d", tc.v, tc.exp, got) } } } func TestNto(t *testing.T) { var ntoTests = []struct { v int64 exp int64 }{{0x00, 0}, {0x01, 1}, {0x0F, 4}, {0xFF, 8}, {0xffffFFFF, 32}, {-0x01, 64}} for _, tc := range ntoTests { if got := nto(tc.v); got != tc.exp { t.Errorf("expected nto(0x%X) = %d, got %d", tc.v, tc.exp, got) } } } func TestLog2(t *testing.T) { var log2Tests = []struct { v int64 exp int64 }{{0, -1}, // nlz expects log2(0) == -1 {1, 0}, {2, 1}, {4, 2}, {1024, 10}} for _, tc := range log2Tests { if got := log2(tc.v); got != tc.exp { t.Errorf("expected log2(%d) = %d, got %d", tc.v, tc.exp, got) } } }