From 323dc634b984b7d30e10b82ae4e9536559488f70 Mon Sep 17 00:00:00 2001
From: Nikita Popov <nikita.ppv@gmail.com>
Date: Mon, 13 May 2019 19:40:18 +0000
Subject: [PATCH] [WebAssembly] Don't assume that zext/sext result is i32/i64
 in fast isel (PR41841)

Usually this will abort fast-isel at the instruction using the
non-legal result, but if the only use is in a different basic block,
we'll incorrectly assume that the zext/sext is to i32 (rather than
i128 in this case).

Differential Revision: https://reviews.llvm.org/D61823

llvm-svn: 360616
---
 .../lib/Target/WebAssembly/WebAssemblyFastISel.cpp | 10 ++++--
 llvm/test/CodeGen/WebAssembly/PR41841.ll           | 42 ++++++++++++++++++++++
 2 files changed, 50 insertions(+), 2 deletions(-)
 create mode 100644 llvm/test/CodeGen/WebAssembly/PR41841.ll

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp
index 535a925..39c682d 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp
@@ -523,7 +523,10 @@ unsigned WebAssemblyFastISel::zeroExtend(unsigned Reg, const Value *V,
     return Result;
   }
 
-  return zeroExtendToI32(Reg, V, From);
+  if (To == MVT::i32)
+    return zeroExtendToI32(Reg, V, From);
+
+  return 0;
 }
 
 unsigned WebAssemblyFastISel::signExtend(unsigned Reg, const Value *V,
@@ -542,7 +545,10 @@ unsigned WebAssemblyFastISel::signExtend(unsigned Reg, const Value *V,
     return Result;
   }
 
-  return signExtendToI32(Reg, V, From);
+  if (To == MVT::i32)
+    return signExtendToI32(Reg, V, From);
+
+  return 0;
 }
 
 unsigned WebAssemblyFastISel::getRegForUnsignedValue(const Value *V) {
diff --git a/llvm/test/CodeGen/WebAssembly/PR41841.ll b/llvm/test/CodeGen/WebAssembly/PR41841.ll
new file mode 100644
index 0000000..6ebaada
--- /dev/null
+++ b/llvm/test/CodeGen/WebAssembly/PR41841.ll
@@ -0,0 +1,42 @@
+; RUN: llc < %s -O0 -wasm-disable-explicit-locals -wasm-keep-registers -asm-verbose=false | FileCheck %s
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
+declare void @foo(i128)
+
+; CHECK-LABEL: test_zext:
+; CHECK-NEXT: .functype test_zext (i32) -> (){{$}}
+; CHECK-NEXT: i64.extend_i32_u $[[TMP3:[0-9]+]]=, $0{{$}}
+; CHECK-NEXT: i64.const $[[TMP4:[0-9]+]]=, 1{{$}}
+; CHECK-NEXT: i64.and $[[TMP1:[0-9]+]]=, $[[TMP3]], $[[TMP4]]{{$}}
+; CHECK-NEXT: i64.const $[[TMP2:[0-9]+]]=, 0{{$}}
+; CHECK-NEXT: call foo, $[[TMP1]], $[[TMP2]]{{$}}
+; CHECK-NEXT: return{{$}}
+define void @test_zext(i1 %b) nounwind {
+  %res = zext i1 %b to i128
+  br label %next
+
+next:                                             ; preds = %start
+  call void @foo(i128 %res)
+  ret void
+}
+
+; CHECK-LABEL: test_sext:
+; CHECK-NEXT:.functype test_sext (i32) -> (){{$}}
+; CHECK-NEXT: i64.extend_i32_u $[[TMP3:[0-9]+]]=, $0{{$}}
+; CHECK-NEXT: i64.const $[[TMP4:[0-9]+]]=, 1{{$}}
+; CHECK-NEXT: i64.and $[[TMP5:[0-9]+]]=, $[[TMP3]], $[[TMP4]]{{$}}
+; CHECK-NEXT: i64.const $[[TMP6:[0-9]+]]=, 0{{$}}
+; CHECK-NEXT: i64.sub $[[TMP1:[0-9]+]]=, $[[TMP6]], $[[TMP5]]{{$}}
+; CHECK-NEXT: local.copy $[[TMP2:[0-9]+]]=, $[[TMP1]]{{$}}
+; CHECK-NEXT: call foo, $[[TMP1]], $[[TMP2]]{{$}}
+; CHECK-NEXT: return{{$}}
+define void @test_sext(i1 %b) nounwind {
+  %res = sext i1 %b to i128
+  br label %next
+
+next:                                             ; preds = %start
+  call void @foo(i128 %res)
+  ret void
+}
-- 
2.7.4