Revert "[WebAssembly] Remove threwValue comparison after __wasm_setjm…

…p_test (#86633)" This reverts commit 52431fd. The PR assumed `__threwValue` couldn't be 0, but it could be when the thrown thing is not a longjmp but an exception, so that `if` check was actually necessary.
llvm · Mar 28, 2024 · 6b7ecc7 · 6b7ecc7
1 parent d9e3e11
commit 6b7ecc7
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Showing 3 changed files with 12 additions and 7 deletions.
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
@@ -153,7 +153,7 @@
 ///      %__THREW__.val = __THREW__;
 ///      __THREW__ = 0;
 ///      %__threwValue.val = __threwValue;
-///      if (%__THREW__.val != 0) {
+///      if (%__THREW__.val != 0 & %__threwValue.val != 0) {
 ///        %label = __wasm_setjmp_test(%__THREW__.val, functionInvocationId);
 ///        if (%label == 0)
 ///          emscripten_longjmp(%__THREW__.val, %__threwValue.val);
@@ -712,10 +712,12 @@ void WebAssemblyLowerEmscriptenEHSjLj::wrapTestSetjmp(
   BasicBlock *ThenBB1 = BasicBlock::Create(C, "if.then1", F);
   BasicBlock *ElseBB1 = BasicBlock::Create(C, "if.else1", F);
   BasicBlock *EndBB1 = BasicBlock::Create(C, "if.end", F);
+  Value *ThrewCmp = IRB.CreateICmpNE(Threw, getAddrSizeInt(M, 0));
   Value *ThrewValue = IRB.CreateLoad(IRB.getInt32Ty(), ThrewValueGV,
                                      ThrewValueGV->getName() + ".val");
-  Value *ThrewCmp = IRB.CreateICmpNE(Threw, getAddrSizeInt(M, 0));
-  IRB.CreateCondBr(ThrewCmp, ThenBB1, ElseBB1);
+  Value *ThrewValueCmp = IRB.CreateICmpNE(ThrewValue, IRB.getInt32(0));
+  Value *Cmp1 = IRB.CreateAnd(ThrewCmp, ThrewValueCmp, "cmp1");
+  IRB.CreateCondBr(Cmp1, ThenBB1, ElseBB1);
 
   // Generate call.em.longjmp BB once and share it within the function
   if (!CallEmLongjmpBB) {

diff --git a/llvm/test/CodeGen/WebAssembly/lower-em-ehsjlj.ll b/llvm/test/CodeGen/WebAssembly/lower-em-ehsjlj.ll
@@ -22,8 +22,10 @@ entry:
           to label %try.cont unwind label %lpad
 
 ; CHECK:    entry.split.split:
-; CHECK:      %__threwValue.val = load i32, ptr @__threwValue
-; CHECK-NEXT: %[[CMP:.*]] = icmp ne i32 %__THREW__.val, 0
+; CHECK:      %[[CMP0:.*]] = icmp ne i32 %__THREW__.val, 0
+; CHECK-NEXT: %__threwValue.val = load i32, ptr @__threwValue
+; CHECK-NEXT: %[[CMP1:.*]] = icmp ne i32 %__threwValue.val, 0
+; CHECK-NEXT: %[[CMP:.*]] = and i1 %[[CMP0]], %[[CMP1]]
 ; CHECK-NEXT: br i1 %[[CMP]], label %if.then1, label %if.else1
 
 ; This is exception checking part. %if.else1 leads here
@@ -119,7 +121,6 @@ if.end:                                           ; preds = %entry
 ; CHECK-NEXT: unreachable
 
 ; CHECK:    normal:
-; CHECK-NEXT: %__threwValue.val = load i32, ptr @__threwValue, align 4
 ; CHECK-NEXT: icmp ne i32 %__THREW__.val, 0
 
 return:                                           ; preds = %if.end, %entry

diff --git a/llvm/test/CodeGen/WebAssembly/lower-em-sjlj.ll b/llvm/test/CodeGen/WebAssembly/lower-em-sjlj.ll
@@ -37,8 +37,10 @@ entry:
 ; CHECK-NEXT: call cc{{.*}} void @__invoke_void_[[PTR]]_i32(ptr @emscripten_longjmp, [[PTR]] %[[JMPBUF]], i32 1)
 ; CHECK-NEXT: %[[__THREW__VAL:.*]] = load [[PTR]], ptr @__THREW__
 ; CHECK-NEXT: store [[PTR]] 0, ptr @__THREW__
+; CHECK-NEXT: %[[CMP0:.*]] = icmp ne [[PTR]] %__THREW__.val, 0
 ; CHECK-NEXT: %[[THREWVALUE_VAL:.*]] = load i32, ptr @__threwValue
-; CHECK-NEXT: %[[CMP:.*]] = icmp ne [[PTR]] %__THREW__.val, 0
+; CHECK-NEXT: %[[CMP1:.*]] = icmp ne i32 %[[THREWVALUE_VAL]], 0
+; CHECK-NEXT: %[[CMP:.*]] = and i1 %[[CMP0]], %[[CMP1]]
 ; CHECK-NEXT: br i1 %[[CMP]], label %if.then1, label %if.else1
 
 ; CHECK: entry.split.split.split: