[GlobalISel][IRTranslator] Fix switch table lowering to use signed LE not unsigned.

We were miscompiling switch value comparisons with the wrong signedness, which
shows up when we have things like switch case values with i1 types, which end up
being legalized incorrectly.

Fixes PR43383

llvm-svn: 372675

2 files changed, 46 insertions, 4 deletions

diff --git a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
index 1e34739cb03..2ce05ec3968 100644
--- a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -589,8 +589,8 @@ void IRTranslator::emitSwitchCase(SwitchCG::CaseBlock &CB,
     Register CondRHS = getOrCreateVReg(*CB.CmpRHS);
     Cond = MIB.buildICmp(CB.PredInfo.Pred, i1Ty, CondLHS, CondRHS).getReg(0);
   } else {
-    assert(CB.PredInfo.Pred == CmpInst::ICMP_ULE &&
-           "Can only handle ULE ranges");
+    assert(CB.PredInfo.Pred == CmpInst::ICMP_SLE &&
+           "Can only handle SLE ranges");
 
     const APInt& Low = cast<ConstantInt>(CB.CmpLHS)->getValue();
     const APInt& High = cast<ConstantInt>(CB.CmpRHS)->getValue();
@@ -599,7 +599,7 @@ void IRTranslator::emitSwitchCase(SwitchCG::CaseBlock &CB,
     if (cast<ConstantInt>(CB.CmpLHS)->isMinValue(true)) {
       Register CondRHS = getOrCreateVReg(*CB.CmpRHS);
       Cond =
-          MIB.buildICmp(CmpInst::ICMP_ULE, i1Ty, CmpOpReg, CondRHS).getReg(0);
+          MIB.buildICmp(CmpInst::ICMP_SLE, i1Ty, CmpOpReg, CondRHS).getReg(0);
     } else {
       const LLT &CmpTy = MRI->getType(CmpOpReg);
       auto Sub = MIB.buildSub({CmpTy}, CmpOpReg, CondLHS);
@@ -729,7 +729,7 @@ bool IRTranslator::lowerSwitchRangeWorkItem(SwitchCG::CaseClusterIt I,
     MHS = nullptr;
   } else {
     // Check I->Low <= Cond <= I->High.
-    Pred = CmpInst::ICMP_ULE;
+    Pred = CmpInst::ICMP_SLE;
     LHS = I->Low;
     MHS = Cond;
     RHS = I->High;
diff --git a/llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator-switch.ll b/llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator-switch.ll
index f5075216352..969cacb89d1 100644
--- a/llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator-switch.ll
+++ b/llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator-switch.ll
@@ -1412,3 +1412,45 @@ bb4:                                              ; preds = %bb1
 
 declare i64* @ham(i32)
 
+define internal void @bar() unnamed_addr #1 {
+  ; CHECK-LABEL: name: bar
+  ; CHECK: bb.1 (%ir-block.0):
+    unreachable
+}
+
+define i1 @i1_value_cmp_is_signed(i1) {
+  ; CHECK-LABEL: name: i1_value_cmp_is_signed
+  ; CHECK: bb.1.Entry:
+  ; CHECK:   successors: %bb.3(0x40000000), %bb.2(0x40000000)
+  ; CHECK:   liveins: $w0
+  ; CHECK:   [[COPY:%[0-9]+]]:_(s32) = COPY $w0
+  ; CHECK:   [[TRUNC:%[0-9]+]]:_(s1) = G_TRUNC [[COPY]](s32)
+  ; CHECK:   [[C:%[0-9]+]]:_(s1) = G_CONSTANT i1 true
+  ; CHECK:   [[C1:%[0-9]+]]:_(s1) = G_CONSTANT i1 false
+  ; CHECK:   [[ICMP:%[0-9]+]]:_(s1) = G_ICMP intpred(sle), [[TRUNC]](s1), [[C1]]
+  ; CHECK:   G_BRCOND [[ICMP]](s1), %bb.3
+  ; CHECK:   G_BR %bb.2
+  ; CHECK: bb.2.BadValue:
+  ; CHECK:   successors:
+  ; CHECK:   ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+  ; CHECK:   BL @bar, csr_aarch64_aapcs, implicit-def $lr, implicit $sp
+  ; CHECK:   ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+  ; CHECK: bb.3.OkValue:
+  ; CHECK:   [[ZEXT:%[0-9]+]]:_(s8) = G_ZEXT [[TRUNC]](s1)
+  ; CHECK:   [[ANYEXT:%[0-9]+]]:_(s32) = G_ANYEXT [[ZEXT]](s8)
+  ; CHECK:   $w0 = COPY [[ANYEXT]](s32)
+  ; CHECK:   RET_ReallyLR implicit $w0
+Entry:
+  switch i1 %0, label %BadValue [
+    i1 false, label %OkValue
+    i1 true, label %OkValue
+  ]
+
+BadValue:
+  call fastcc void @bar()
+  unreachable
+
+OkValue:
+  ret i1 %0
+}
+