[AArch64][GlobalISel]: Fix a crash in GlobalIsel in dealing with 16bit uadd.with.overflow.

[xiaoqing_wu]

Summary

AArch64 doesn't support uadd.with.overflow.i16 natively. This change adds a legalization rule to convert the 32bit add result to 16bit. This should fix PR43981.

[paquette]

Thanks for fixing this!

LGTM with some minor nits on the test.

Also, can you rename the test to "legalize-uaddo.mir"? That way we can reuse it for any future legalization work we might have to do for G_UADDO.

llvm/test/CodeGen/AArch64/test-uadd16-with-overflow.mir

2 ↗

(On Diff #234213)

I would add -verify-machineinstrs to the RUN line here.

9–20 ↗

(On Diff #234213)

I'm pretty sure you can delete the registers, liveins, frameInfo, and machineFunctionInfo sections in this test. The legalizer doesn't use any of this information, and so it's not necessary to keep it.

[xiaoqing_wu]

Updated the test case according to review comment.

[xiaoqing_wu]

Remove old test case

[xiaoqing_wu]

• Merge branch 'master' of https://github.com/llvm/llvm-project

llvm/lib/Target/AArch64/AArch64LegalizerInfo.cpp

getActionDefinitionsBuilder({G_SREM, G_UREM})
       .lowerFor({s1, s8, s16, s32, s64});
 
   getActionDefinitionsBuilder({G_SMULO, G_UMULO})
       .lowerFor({{s64, s1}});
 
   getActionDefinitionsBuilder({G_SMULH, G_UMULH}).legalFor({s32, s64});
 
   getActionDefinitionsBuilder({G_UADDE, G_USUBE, G_SADDO, G_SSUBO, G_UADDO})
-      .legalFor({{s32, s1}, {s64, s1}});
+      .legalFor({{s32, s1}, {s64, s1}})
+      .minScalar(0, s32);
 
   getActionDefinitionsBuilder({G_FADD, G_FSUB, G_FMUL, G_FDIV, G_FNEG})
     .legalFor({s32, s64, v2s64, v4s32, v2s32});
 
   getActionDefinitionsBuilder(G_FREM).libcallFor({s32, s64});
 
   getActionDefinitionsBuilder({G_FCEIL, G_FABS, G_FSQRT, G_FFLOOR, G_FRINT,
                                G_FMA, G_INTRINSIC_TRUNC, G_INTRINSIC_ROUND,

llvm/test/CodeGen/AArch64/legalize-uaddo.mir

+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc %s -run-pass legalizer -march=arm64 -global-isel=1 -verify-machineinstrs -o - | FileCheck %s
+
+...
+---
+name:            legalize-uaddo
+alignment:       4
+tracksRegLiveness: true
+body:             |
+  bb.1:
+    liveins: $x0
+
+    ; CHECK-LABEL: name: legalize-uaddo
+    ; CHECK: liveins: $x0
+    ; CHECK: [[COPY:%[0-9]+]]:_(s64) = COPY $x0
+    ; CHECK: [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 65535
+    ; CHECK: [[TRUNC:%[0-9]+]]:_(s32) = G_TRUNC [[COPY]](s64)
+    ; CHECK: [[AND:%[0-9]+]]:_(s32) = G_AND [[TRUNC]], [[C]]
+    ; CHECK: [[C1:%[0-9]+]]:_(s32) = G_CONSTANT i32 2
+    ; CHECK: [[ADD:%[0-9]+]]:_(s32) = G_ADD [[AND]], [[C1]]
+    ; CHECK: [[AND1:%[0-9]+]]:_(s32) = G_AND [[ADD]], [[C]]
+    ; CHECK: [[ICMP:%[0-9]+]]:_(s32) = G_ICMP intpred(ne), [[ADD]](s32), [[AND1]]
+    ; CHECK: [[C2:%[0-9]+]]:_(s64) = G_CONSTANT i64 1
+    ; CHECK: [[ANYEXT:%[0-9]+]]:_(s64) = G_ANYEXT [[ICMP]](s32)
+    ; CHECK: [[AND2:%[0-9]+]]:_(s64) = G_AND [[ANYEXT]], [[C2]]
+    ; CHECK: $x0 = COPY [[AND2]](s64)
+    ; CHECK: RET_ReallyLR implicit $x0
+    %0:_(s64) = COPY $x0
+    %4:_(s16) = G_CONSTANT i16 2
+    %1:_(s16) = G_TRUNC %0(s64)
+    %2:_(s16), %3:_(s1) = G_UADDO %1, %4
+    %5:_(s64) = G_ZEXT %3(s1)
+    $x0 = COPY %5(s64)
+    RET_ReallyLR implicit $x0
+
+...