[WebAssembly] Lower away condition truncations for scalar selects

tlively · tlively · commit eb15d00193f7 · 2018-10-29T18:38:12.000Z
Reviewers: aheejin, dschuff Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits Differential Revision: https://reviews.llvm.org/D53676 llvm-svn: 345521
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyInstrFloat.td b/llvm/lib/Target/WebAssembly/WebAssemblyInstrFloat.td
@@ -122,3 +122,10 @@ def : Pat<(select (i32 (seteq I32:$cond, 0)), F32:$lhs, F32:$rhs),
           (SELECT_F32 F32:$rhs, F32:$lhs, I32:$cond)>;
 def : Pat<(select (i32 (seteq I32:$cond, 0)), F64:$lhs, F64:$rhs),
           (SELECT_F64 F64:$rhs, F64:$lhs, I32:$cond)>;
+
+// The legalizer inserts an unnecessary `and 1` to make input conform
+// to getBooleanContents, which we can lower away.
+def : Pat<(select (i32 (and I32:$cond, 1)), F32:$lhs, F32:$rhs),
+          (SELECT_F32 F32:$lhs, F32:$rhs, I32:$cond)>;
+def : Pat<(select (i32 (and I32:$cond, 1)), F64:$lhs, F64:$rhs),
+          (SELECT_F64 F64:$lhs, F64:$rhs, I32:$cond)>;
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyInstrInteger.td b/llvm/lib/Target/WebAssembly/WebAssemblyInstrInteger.td
@@ -122,3 +122,10 @@ def : Pat<(select (i32 (seteq I32:$cond, 0)), I32:$lhs, I32:$rhs),
           (SELECT_I32 I32:$rhs, I32:$lhs, I32:$cond)>;
 def : Pat<(select (i32 (seteq I32:$cond, 0)), I64:$lhs, I64:$rhs),
           (SELECT_I64 I64:$rhs, I64:$lhs, I32:$cond)>;
+
+// The legalizer inserts an unnecessary `and 1` to make input conform
+// to getBooleanContents, which we can lower away.
+def : Pat<(select (i32 (and I32:$cond, 1)), I32:$lhs, I32:$rhs),
+          (SELECT_I32 I32:$lhs, I32:$rhs, I32:$cond)>;
+def : Pat<(select (i32 (and I32:$cond, 1)), I64:$lhs, I64:$rhs),
+          (SELECT_I64 I64:$lhs, I64:$rhs, I32:$cond)>;
diff --git a/llvm/test/CodeGen/WebAssembly/select.ll b/llvm/test/CodeGen/WebAssembly/select.ll
@@ -1,4 +1,4 @@
-; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers | FileCheck %s
+; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers | FileCheck %s --check-prefixes CHECK,SLOW
 ; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -fast-isel -fast-isel-abort=1 | FileCheck %s
 
 ; Test that wasm select instruction is selected from LLVM select instruction.
@@ -16,6 +16,16 @@ define i32 @select_i32_bool(i1 zeroext %a, i32 %b, i32 %c) {
   ret i32 %cond
 }
 
+; CHECK-LABEL: select_i32_bool_nozext:
+; CHECK-NEXT: .param     i32, i32, i32{{$}}
+; CHECK-NEXT: .result    i32{{$}}
+; SLOW-NEXT: i32.select $push0=, $1, $2, $0{{$}}
+; SLOW-NEXT: return     $pop0{{$}}
+define i32 @select_i32_bool_nozext(i1 %a, i32 %b, i32 %c) {
+  %cond = select i1 %a, i32 %b, i32 %c
+  ret i32 %cond
+}
+
 ; CHECK-LABEL: select_i32_eq:
 ; CHECK-NEXT: .param     i32, i32, i32{{$}}
 ; CHECK-NEXT: .result    i32{{$}}
@@ -48,6 +58,16 @@ define i64 @select_i64_bool(i1 zeroext %a, i64 %b, i64 %c) {
   ret i64 %cond
 }
 
+; CHECK-LABEL: select_i64_bool_nozext:
+; CHECK-NEXT: .param     i32, i64, i64{{$}}
+; CHECK-NEXT: .result    i64{{$}}
+; SLOW-NEXT: i64.select $push0=, $1, $2, $0{{$}}
+; SLOW-NEXT: return     $pop0{{$}}
+define i64 @select_i64_bool_nozext(i1 %a, i64 %b, i64 %c) {
+  %cond = select i1 %a, i64 %b, i64 %c
+  ret i64 %cond
+}
+
 ; CHECK-LABEL: select_i64_eq:
 ; CHECK-NEXT: .param     i32, i64, i64{{$}}
 ; CHECK-NEXT: .result    i64{{$}}
@@ -80,6 +100,16 @@ define float @select_f32_bool(i1 zeroext %a, float %b, float %c) {
   ret float %cond
 }
 
+; CHECK-LABEL: select_f32_bool_nozext:
+; CHECK-NEXT: .param     i32, f32, f32{{$}}
+; CHECK-NEXT: .result    f32{{$}}
+; SLOW-NEXT: f32.select $push0=, $1, $2, $0{{$}}
+; SLOW-NEXT: return     $pop0{{$}}
+define float @select_f32_bool_nozext(i1 %a, float %b, float %c) {
+  %cond = select i1 %a, float %b, float %c
+  ret float %cond
+}
+
 ; CHECK-LABEL: select_f32_eq:
 ; CHECK-NEXT: .param     i32, f32, f32{{$}}
 ; CHECK-NEXT: .result    f32{{$}}
@@ -112,6 +142,16 @@ define double @select_f64_bool(i1 zeroext %a, double %b, double %c) {
   ret double %cond
 }
 
+; CHECK-LABEL: select_f64_bool_nozext:
+; CHECK-NEXT: .param     i32, f64, f64{{$}}
+; CHECK-NEXT: .result    f64{{$}}
+; SLOW-NEXT: f64.select $push0=, $1, $2, $0{{$}}
+; SLOW-NEXT: return     $pop0{{$}}
+define double @select_f64_bool_nozext(i1 %a, double %b, double %c) {
+  %cond = select i1 %a, double %b, double %c
+  ret double %cond
+}
+
 ; CHECK-LABEL: select_f64_eq:
 ; CHECK-NEXT: .param     i32, f64, f64{{$}}
 ; CHECK-NEXT: .result    f64{{$}}
