libgo/testsuite: add benchmarks and examples to list

In CL 384695 I simplified the code that built lists of benchmarks,
examples, and fuzz tests, and managed to break it. This CL corrects
the code to once again make the benchmarks available, and to run
the examples with output and the fuzz targets.

Doing this revealed a test failure in internal/fuzz on 32-bit x86:
a signalling NaN is turned into a quiet NaN on the 387 floating-point
stack that GCC uses by default. This CL skips the test.

Fixes golang/go#60826

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/503798

gcc/go/gofrontend/MERGE

@@ -1,4 +1,4 @@
-737de90a63002d4872b19772a7116404ee5815b4
+a3a3c3a2d1bc6a8ca51b302d08c94ef27cdd8f0f
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

libgo/go/internal/fuzz/encoding_test.go

@@ -6,6 +6,7 @@ package fuzz
 
 import (
 	"math"
+	"runtime"
 	"strconv"
 	"testing"
 	"unicode"
@@ -330,6 +331,14 @@ func FuzzFloat64RoundTrip(f *testing.F) {
 	f.Add(math.Float64bits(math.Inf(-1)))
 
 	f.Fuzz(func(t *testing.T, u1 uint64) {
+		// The signaling NaN test fails on 32-bit x86 with gccgo,
+		// which uses the 387 floating-point stack by default.
+		// Converting a signaling NaN in and out of the stack
+		// changes the NaN to a quiet NaN.
+		if runtime.GOARCH == "386" && u1 == 0x7FF0000000000001 {
+			t.Skip("skipping signalling NaN test on 386 with gccgo")
+		}
+
 		x1 := math.Float64frombits(u1)
 
 		b := marshalCorpusFile(x1)

libgo/testsuite/gotest

@@ -577,13 +577,13 @@ symtogo() {
 # Find Go benchmark/fuzz/example functions.
 # The argument is the function name prefix.
 findfuncs() {
-	pattern='$1([^a-z].*)?'
+	pattern="$1([^a-z].*)?"
 	syms=$($NM -p -v _gotest_.o | egrep " $text .*\."$pattern'$' | fgrep -v ' __go_' | egrep -v '\.\.\w+$' | sed 's/.* //')
 	if $havex; then
 	    xsyms=$($NM -p -v $xofile | egrep " $text .*\."$pattern'$' | fgrep -v ' __go_' | egrep -v '\.\.\w+$' | sed 's/.* //')
 	    syms="$syms $xsyms"
 	fi
-        $(symtogo "$benchmarksyms")
+        symtogo "$syms"
 }
 
 # Takes an example name and puts any output into the file example.txt.
@@ -643,11 +643,13 @@ exampleoutput() {
 	fi
 	if $havex; then
 	    needxtest=false
-	    if test -n "$testxsyms" -o -n "$benchmarkxsyms"; then
+	    if test -n "$testxsyms"; then
+		needxtest=true
+	    elif echo "$benchmarks" | grep '_test\.' >/dev/null; then
 		needxtest=true
 	    else
 		# Check whether any example has output.
-		for i in $(symtogo "$examplexsyms"); do
+		for i in $(echo "$examples" | grep '_test\.'); do
 		    exampleoutput $i
 		    if test -f example.txt; then
 			rm -f example.txt