diff --git a/.github/workflows/compare_pr_to_master.v b/.github/workflows/compare_pr_to_master.v
new file mode 100755
index 0000000000..0d48b09b49
--- /dev/null
+++ b/.github/workflows/compare_pr_to_master.v
@@ -0,0 +1,74 @@
+import os
+import time
+
+const compare_prod = '-prod' in os.args
+
+fn gbranch() string {
+	return os.execute(r'git branch --list|grep ^\*').output.trim_space()
+}
+
+fn gcommit() string {
+	return os.execute(r'git rev-parse --short=7 HEAD').output.trim_space()
+}
+
+fn r(cmd string) {
+	os.system(cmd)
+}
+
+fn xtime(cmd string) {
+	$if windows {
+		before := time.now()
+		r(cmd)
+		after := time.now()
+		delta_time := after - before
+		println('> Elapsed time: ${delta_time.milliseconds()} ms, for cmd: ${cmd}')
+	} $else {
+		r('/usr/bin/time -f "CPU: %Us\tReal: %es\tElapsed: %E\tRAM: %MKB\t%C" ${cmd}')
+	}
+}
+
+fn vcompare(vold string, vnew string) {
+	r("v repeat -R 3 '${vold} -check-syntax examples/hello_world.v' '${vnew} -check-syntax examples/hello_world.v'")
+	r("v repeat -R 3 '${vold} -check        examples/hello_world.v' '${vnew} -check        examples/hello_world.v'")
+	r("v repeat -R 3 '${vold} -o    hw.c    examples/hello_world.v' '${vnew} -o    hw.c    examples/hello_world.v'")
+	r("v repeat -R 3 '${vold} -o    hw      examples/hello_world.v' '${vnew} -o    hw      examples/hello_world.v'")
+	r("v repeat -R 3 '${vold} -check-syntax cmd/v'                  '${vnew} -check-syntax cmd/v'")
+	r("v repeat -R 3 '${vold} -check        cmd/v'                  '${vnew} -check        cmd/v'")
+	r("v repeat -R 3 '${vold} -o    ov.c    cmd/v'                  '${vnew} -o    nv.c    cmd/v'")
+	r("v repeat -R 3 '${vold} -o    ov      cmd/v'                  '${vnew} -o    nv      cmd/v'")
+}
+
+fn main() {
+	// The starting point, when this program should be started, is just after `gh pr checkout NUMBER`.
+
+	println('Current git branch: ${gbranch()}, commit: ${gcommit()}')
+	println('    Compiling new V executables from PR branch: ${gbranch()}, commit: ${gcommit()} ...')
+	xtime('./v     -o vnew1 cmd/v')
+	xtime('./vnew1 -o vnew2 cmd/v')
+	xtime('./vnew2 -o vnew  cmd/v')
+	r('rm -rf vnew1 vnew2')
+	if compare_prod {
+		xtime('./vnew -prod -o vnew_prod cmd/v')
+	}
+
+	r('git checkout master')
+
+	println('    Compiling old V executables from branch: ${gbranch()}, commit: ${gcommit()} ...')
+	xtime('./v     -o vold1 cmd/v')
+	xtime('./vold1 -o vold2 cmd/v')
+	xtime('./vold2 -o vold  cmd/v')
+	r('rm -rf vold1 vold2')
+	if compare_prod {
+		xtime('./vold -prod -o vold_prod cmd/v')
+	}
+
+	r('git switch -') // we are on the PR branch again
+
+	println('    Measuring at PR branch: ${gbranch()}, commit: ${gcommit()} ...')
+	if compare_prod {
+		vcompare('./vold_prod', './vnew_prod')
+	} else {
+		vcompare('./vold', './vnew')
+	}
+	println('Done.')
+}