[WebAssembly][FastISel] Do not assume naive CmpInst lowering
Summary:
Fixes https://bugs.llvm.org/show_bug.cgi?id=40172. See
test/CodeGen/WebAssembly/PR40172.ll for an explanation.
Reviewers: dschuff, aheejin
Subscribers: nikic, llvm-commits, sunfish, jgravelle-google, sbc100
Differential Revision: https://reviews.llvm.org/D56457
llvm-svn: 351127
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp
index 527908d..3856700 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp
@@ -443,13 +443,11 @@
switch (From) {
case MVT::i1:
- // If the value is naturally an i1, we don't need to mask it.
- // TODO: Recursively examine selects, phis, and, or, xor, constants.
- if (From == MVT::i1 && V != nullptr) {
- if (isa<CmpInst>(V) ||
- (isa<Argument>(V) && cast<Argument>(V)->hasZExtAttr()))
- return copyValue(Reg);
- }
+ // If the value is naturally an i1, we don't need to mask it. We only know
+ // if a value is naturally an i1 if it is definitely lowered by FastISel,
+ // not a DAG ISel fallback.
+ if (V != nullptr && isa<Argument>(V) && cast<Argument>(V)->hasZExtAttr())
+ return copyValue(Reg);
break;
case MVT::i8:
case MVT::i16: