[PATCH] D78378: [GlobalISel][IRTranslator] Fix <1 x Ty> handling in ConstantExprs

[Jay Foad via Phabricator via llvm-commits]

foad created this revision.
foad added reviewers: arsenm, volkan, t.p.northover, aditya_nandakumar.
Herald added subscribers: llvm-commits, kerbowa, hiraditya, rovka, nhaehnle, wdng, jvesely.
Herald added a project: LLVM.
foad added a parent revision: D78377: [GlobalISel][IRTranslator] New helper function translateCopy. NFC..

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


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D78378

Files:
  llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
  llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
  llvm/test/CodeGen/AMDGPU/GlobalISel/irtranslator-constantexpr.ll


Index: llvm/test/CodeGen/AMDGPU/GlobalISel/irtranslator-constantexpr.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AMDGPU/GlobalISel/irtranslator-constantexpr.ll
@@ -0,0 +1,24 @@
+; NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+; RUN: llc -global-isel -mtriple=amdgcn-amd-amdhsa -verify-machineinstrs -stop-after=irtranslator -o - %s | FileCheck %s
+
+ at var = global i32 undef
+
+define i32 @test() {
+  ; CHECK-LABEL: name: test
+  ; CHECK: bb.1 (%ir-block.0):
+  ; CHECK:   liveins: $sgpr30_sgpr31
+  ; CHECK:   [[COPY:%[0-9]+]]:sgpr_64 = COPY $sgpr30_sgpr31
+  ; CHECK:   [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 -1
+  ; CHECK:   [[INTTOPTR:%[0-9]+]]:_(p0) = G_INTTOPTR [[C]](s32)
+  ; CHECK:   [[GV:%[0-9]+]]:_(p0) = G_GLOBAL_VALUE @var
+  ; CHECK:   [[ICMP:%[0-9]+]]:_(s1) = G_ICMP intpred(eq), [[INTTOPTR]](p0), [[GV]]
+  ; CHECK:   [[ZEXT:%[0-9]+]]:_(s32) = G_ZEXT [[ICMP]](s1)
+  ; CHECK:   [[COPY1:%[0-9]+]]:_(s32) = COPY [[ZEXT]](s32)
+  ; CHECK:   [[COPY2:%[0-9]+]]:_(s32) = COPY [[COPY1]](s32)
+  ; CHECK:   [[COPY3:%[0-9]+]]:_(s32) = COPY [[COPY2]](s32)
+  ; CHECK:   [[COPY4:%[0-9]+]]:_(s32) = COPY [[COPY3]](s32)
+  ; CHECK:   $vgpr0 = COPY [[COPY4]](s32)
+  ; CHECK:   [[COPY5:%[0-9]+]]:ccr_sgpr_64 = COPY [[COPY]]
+  ; CHECK:   S_SETPC_B64_return [[COPY5]], implicit $vgpr0
+  ret i32 bitcast (<1 x i32> <i32 extractelement (<1 x i32> bitcast (i32 zext (i1 icmp eq (i32* @var, i32* inttoptr (i32 -1 to i32*)) to i32) to <1 x i32>), i64 0)> to i32)
+}
Index: llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
===================================================================
--- llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
+++ llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
@@ -1614,7 +1614,9 @@
 ; CHECK: [[ARG:%[0-9]+]]:_(s32) = COPY $w0
 ; CHECK: [[C0:%[0-9]+]]:_(s32) = G_CONSTANT i32 0
 ; CHECK-NOT: G_MERGE_VALUES
-; CHECK: G_ADD [[ARG]], [[C0]]
+; CHECK: [[COPY:%[0-9]+]]:_(s32) = COPY [[C0]]
+; CHECK-NOT: G_MERGE_VALUES
+; CHECK: G_ADD [[ARG]], [[COPY]]
   %vec = insertelement <1 x i32> undef, i32 %arg, i32 0
   %add = add <1 x i32> %vec, zeroinitializer
   %res = extractelement <1 x i32> %add, i32 0
@@ -1626,7 +1628,9 @@
 ; CHECK: [[ARG:%[0-9]+]]:_(s32) = COPY $w0
 ; CHECK: [[C1:%[0-9]+]]:_(s32) = G_CONSTANT i32 1
 ; CHECK-NOT: G_MERGE_VALUES
-; CHECK: G_ADD [[ARG]], [[C1]]
+; CHECK: [[COPY:%[0-9]+]]:_(s32) = COPY [[C0]]
+; CHECK-NOT: G_MERGE_VALUES
+; CHECK: G_ADD [[ARG]], [[COPY]]
   %vec = insertelement <1 x i32> undef, i32 %arg, i32 0
   %add = add <1 x i32> %vec, <i32 1>
   %res = extractelement <1 x i32> %add, i32 0
@@ -2388,4 +2392,4 @@
   ret {i8, i32} %res
 }
 
-!0 = !{ i64 0, i64 2 }
\ No newline at end of file
+!0 = !{ i64 0, i64 2 }
Index: llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
===================================================================
--- llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -2184,7 +2184,7 @@
       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);
@@ -2194,7 +2194,8 @@
   } 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);
@@ -2212,7 +2213,7 @@
     }
   } 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)));


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