[GlobalISel][IRTranslator] Fix <1 x Ty> handling in ConstantExprs

Summary:
ConstantExprs involving operations on <1 x Ty> could translate into MIR
that failed to verify with:
*** Bad machine code: Reading virtual register without a def ***

The problem was that translate(const Constant &C, Register Reg) had
recursive calls that passed the same Reg in for the translation of a
subexpression, but without updating VMap for the subexpression first as
translate(const Constant &C, Register Reg) expects.

Fix this by using the same translateCopy helper function that we use for
translating Instructions. In some cases this causes extra G_COPY
MIR instructions to be generated.

Fixes https://bugs.llvm.org/show_bug.cgi?id=45576

Reviewers: arsenm, volkan, t.p.northover, aditya_nandakumar

Subscribers: jvesely, wdng, nhaehnle, rovka, hiraditya, kerbowa, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78378

1 files changed, 4 insertions, 3 deletions

diff --git a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
index 4a2cbbb..109f86f 100644
--- a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -2173,7 +2173,7 @@ bool IRTranslator::translate(const Constant &C, Register Reg) {
       return false;
     // Return the scalar if it is a <1 x Ty> vector.
     if (CAZ->getNumElements() == 1)
-      return translate(*CAZ->getElementValue(0u), Reg);
+      return translateCopy(C, *CAZ->getElementValue(0u), *EntryBuilder.get());
     SmallVector<Register, 4> Ops;
     for (unsigned i = 0; i < CAZ->getNumElements(); ++i) {
       Constant &Elt = *CAZ->getElementValue(i);
@@ -2183,7 +2183,8 @@ bool IRTranslator::translate(const Constant &C, Register Reg) {
   } else if (auto CV = dyn_cast<ConstantDataVector>(&C)) {
     // Return the scalar if it is a <1 x Ty> vector.
     if (CV->getNumElements() == 1)
-      return translate(*CV->getElementAsConstant(0), Reg);
+      return translateCopy(C, *CV->getElementAsConstant(0),
+                           *EntryBuilder.get());
     SmallVector<Register, 4> Ops;
     for (unsigned i = 0; i < CV->getNumElements(); ++i) {
       Constant &Elt = *CV->getElementAsConstant(i);
@@ -2201,7 +2202,7 @@ bool IRTranslator::translate(const Constant &C, Register Reg) {
     }
   } else if (auto CV = dyn_cast<ConstantVector>(&C)) {
     if (CV->getNumOperands() == 1)
-      return translate(*CV->getOperand(0), Reg);
+      return translateCopy(C, *CV->getOperand(0), *EntryBuilder.get());
     SmallVector<Register, 4> Ops;
     for (unsigned i = 0; i < CV->getNumOperands(); ++i) {
       Ops.push_back(getOrCreateVReg(*CV->getOperand(i)));