9c70781236
Bump CI Go versions to 1.16 and 1.17. Update build tags with `go:build` equivalents. Upgrade asmfmt tool for new `go:build` support. Updates #183
68 lines
1.5 KiB
Go
68 lines
1.5 KiB
Go
//go:build ignore
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// +build ignore
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package main
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import (
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"strconv"
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. "github.com/mmcloughlin/avo/build"
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. "github.com/mmcloughlin/avo/operand"
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. "github.com/mmcloughlin/avo/reg"
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)
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// The goal is to test for correct handling of 32-bit operands in 64-bit mode,
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// specifically that writes are zero-extended to 64 bits. This test is
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// constructed such that the register allocator would fail if this feature is
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// not accounted for. It consists of multiple copies of a 32-bit write followed
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// by a 64-bit read of the same register. Without special treatment liveness
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// analysis would consider the upper 32 bits to still be live prior to the
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// write. Therefore if we stack up enough copies of this, we could cause the
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// register allocator to fail.
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func main() {
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const (
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r = 14 // number of registers
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m = 3 // number of iterations
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n = r * m
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)
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TEXT("Upper32", NOSPLIT, "func() uint64")
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Doc("Upper32 computes the sum 1+2+...+" + strconv.Itoa(n) + ".")
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Comment("Initialize sum.")
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s := GP64()
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XORQ(s, s)
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// Allocate n 64-bit registers and populate them.
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Comment("Initialize registers.")
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x := make([]GPVirtual, n)
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for i := 0; i < n; i++ {
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x[i] = GP64()
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MOVQ(U64(0x9e77d78aacb8cbcc), x[i])
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}
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k := 0
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for i := 0; i < m; i++ {
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Commentf("Iteration %d.", i+1)
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// Write to the 32-bit aliases of r registers.
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for j := 0; j < r; j++ {
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MOVL(U32(k+j+1), x[k+j].As32())
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}
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// Sum them up.
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for j := 0; j < r; j++ {
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ADDQ(x[k+j], s)
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}
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k += r
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}
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Comment("Store result and return.")
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Store(s, ReturnIndex(0))
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RET()
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Generate()
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}
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