Add static for loop iteration inference. (#2659)

1 files changed, 60 insertions, 0 deletions

diff --git a/tests/diagnostics/for-loop-warning.slang b/tests/diagnostics/for-loop-warning.slang
new file mode 100644
index 000000000..226af46f5
--- /dev/null
+++ b/tests/diagnostics/for-loop-warning.slang
@@ -0,0 +1,60 @@
+//DIAGNOSTIC_TEST:SIMPLE:
+
+
+float doSomething(int x)
+{
+    for (int i = 0; i < x; i--) // warn.
+    {}
+    for (int i = 0; i < 5; i-=-2) // ok.
+    {}
+    for (int j = 0; j < 3; j += 0) // warn.
+    {}
+    for (int i = 0; i < 5; i++) // ok
+    {
+        for (int j = 0; j < 3; i++) // warn.
+        {}
+    }
+    for (int i = 0; i < 5; i++) // ok
+    {
+        for (int j = 0; i < 4; j++) // warn.
+        {}
+    }
+
+    [MaxIters(6)] // warn
+    for (int i = 0; i <= 6; i+=3)
+    {
+    }
+
+    [MaxIters(6)] // warn
+    for (int i = 5; i >= 0; i -= 3)
+    {
+    }
+    [MaxIters(6)] // warn
+    for (int i = 5; i > 0; i--)
+    {
+    }
+
+    [MaxIters(5)] // ok
+    for (int i = 0; i < 5; i++) // ok
+    {
+    }
+
+    for (int i = 1; i < 0; i++) // warn
+    {
+    }
+    for (int i = 1; i >= 2; i--) // warn
+    {
+    }
+    for (int i = 1; i >= 1; i--) // ok
+    {
+    }
+    for (int i = 1; i > 1; i--) // warn
+    {
+    }
+    [MaxIters(5)] // ok, because the loop body modifies i so we can't infer the iterations.
+    for (int i = 0; i < 5; i+=2)
+    {
+        i--;
+    }
+    return 0.0;
+}