1 files changed, 31 insertions, 0 deletions
diff --git a/test/CodeGen/WebAssembly/PR40172.ll b/test/CodeGen/WebAssembly/PR40172.ll
new file mode 100644
index 000000000000..e0ad5be8b219
--- /dev/null
+++ b/test/CodeGen/WebAssembly/PR40172.ll
@@ -0,0 +1,31 @@
+; RUN: llc < %s -O0 -wasm-disable-explicit-locals -wasm-keep-registers | FileCheck %s
+
+; Regression test for bug 40172. The problem was that FastISel assumed
+; that CmpInst results did not need to be zero extended because
+; WebAssembly's compare instructions always return 0 or 1. But in this
+; test case FastISel falls back to DAG ISel, which combines away the
+; comparison, invalidating FastISel's assumption.
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
+; CHECK:  i32.sub $[[BASE:[0-9]+]]=,
+; CHECK:  local.copy $[[ARG:[0-9]+]]=, $0{{$}}
+; CHECK:  i32.const $[[A0:[0-9]+]]=, 1{{$}}
+; CHECK:  i32.and $[[A1:[0-9]+]]=, $[[ARG]], $[[A0]]{{$}}
+; CHECK:  i32.store8 8($[[BASE]]), $[[A1]]{{$}}
+
+define void @test(i8 %byte) {
+  %t = alloca { i8, i8 }, align 1
+  %x4 = and i8 %byte, 1
+  %x5 = icmp eq i8 %x4, 1
+  %x6 = and i8 %byte, 2
+  %x7 = icmp eq i8 %x6, 2
+  %x8 = bitcast { i8, i8 }* %t to i8*
+  %x9 = zext i1 %x5 to i8
+  store i8 %x9, i8* %x8, align 1
+  %x10 = getelementptr inbounds { i8, i8 }, { i8, i8 }* %t, i32 0, i32 1
+  %x11 = zext i1 %x7 to i8
+  store i8 %x11, i8* %x10, align 1
+  ret void
+}