3 files changed, 42 insertions, 0 deletions
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyInstrInteger.td b/llvm/lib/Target/WebAssembly/WebAssemblyInstrInteger.td
index cf2c6a38d51..16ed7acbb9d 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyInstrInteger.td
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyInstrInteger.td
@@ -40,3 +40,9 @@ defm UGE : ComparisonInt<SETUGE>;
 defm CLZ : UnaryInt<ctlz>;
 defm CTZ : UnaryInt<cttz>;
 defm POPCNT : UnaryInt<ctpop>;
+
+// Expand the "don't care" operations to supported operations.
+def : Pat<(ctlz_zero_undef Int32:$src), (CLZ_I32 Int32:$src)>;
+def : Pat<(ctlz_zero_undef Int64:$src), (CLZ_I64 Int64:$src)>;
+def : Pat<(cttz_zero_undef Int32:$src), (CTZ_I32 Int32:$src)>;
+def : Pat<(cttz_zero_undef Int64:$src), (CTZ_I64 Int64:$src)>;
diff --git a/llvm/test/CodeGen/WebAssembly/integer32.ll b/llvm/test/CodeGen/WebAssembly/integer32.ll
index e987f6eaa55..ab2d0b9497c 100644
--- a/llvm/test/CodeGen/WebAssembly/integer32.ll
+++ b/llvm/test/CodeGen/WebAssembly/integer32.ll
@@ -148,6 +148,15 @@ define i32 @clz32(i32 %x) {
   ret i32 %a
 }
 
+; CHECK-LABEL: clz32_zero_undef:
+; CHECK-NEXT: (setlocal @0 (argument 0))
+; CHECK-NEXT: (setlocal @1 (clz @0))
+; CHECK-NEXT: (return @1)
+define i32 @clz32_zero_undef(i32 %x) {
+  %a = call i32 @llvm.ctlz.i32(i32 %x, i1 true)
+  ret i32 %a
+}
+
 ; CHECK-LABEL: ctz32:
 ; CHECK-NEXT: (setlocal @0 (argument 0))
 ; CHECK-NEXT: (setlocal @1 (ctz @0))
@@ -157,6 +166,15 @@ define i32 @ctz32(i32 %x) {
   ret i32 %a
 }
 
+; CHECK-LABEL: ctz32_zero_undef:
+; CHECK-NEXT: (setlocal @0 (argument 0))
+; CHECK-NEXT: (setlocal @1 (ctz @0))
+; CHECK-NEXT: (return @1)
+define i32 @ctz32_zero_undef(i32 %x) {
+  %a = call i32 @llvm.cttz.i32(i32 %x, i1 true)
+  ret i32 %a
+}
+
 ; CHECK-LABEL: popcnt32:
 ; CHECK-NEXT: (setlocal @0 (argument 0))
 ; CHECK-NEXT: (setlocal @1 (popcnt @0))
diff --git a/llvm/test/CodeGen/WebAssembly/integer64.ll b/llvm/test/CodeGen/WebAssembly/integer64.ll
index ba483552939..f902bced9d9 100644
--- a/llvm/test/CodeGen/WebAssembly/integer64.ll
+++ b/llvm/test/CodeGen/WebAssembly/integer64.ll
@@ -148,6 +148,15 @@ define i64 @clz64(i64 %x) {
   ret i64 %a
 }
 
+; CHECK-LABEL: clz64_zero_undef:
+; CHECK-NEXT: (setlocal @0 (argument 0))
+; CHECK-NEXT: (setlocal @1 (clz @0))
+; CHECK-NEXT: (return @1)
+define i64 @clz64_zero_undef(i64 %x) {
+  %a = call i64 @llvm.ctlz.i64(i64 %x, i1 true)
+  ret i64 %a
+}
+
 ; CHECK-LABEL: ctz64:
 ; CHECK-NEXT: (setlocal @0 (argument 0))
 ; CHECK-NEXT: (setlocal @1 (ctz @0))
@@ -157,6 +166,15 @@ define i64 @ctz64(i64 %x) {
   ret i64 %a
 }
 
+; CHECK-LABEL: ctz64_zero_undef:
+; CHECK-NEXT: (setlocal @0 (argument 0))
+; CHECK-NEXT: (setlocal @1 (ctz @0))
+; CHECK-NEXT: (return @1)
+define i64 @ctz64_zero_undef(i64 %x) {
+  %a = call i64 @llvm.cttz.i64(i64 %x, i1 true)
+  ret i64 %a
+}
+
 ; CHECK-LABEL: popcnt64:
 ; CHECK-NEXT: (setlocal @0 (argument 0))
 ; CHECK-NEXT: (setlocal @1 (popcnt @0))