[llvm] 85e4ee1 - [SystemZ] Avoid type legalization on structs

[Josh Stone via llvm-commits]

Author: Josh Stone
Date: 2023-08-07T17:52:15-07:00
New Revision: 85e4ee15d32ae0344755d11d4ca90a15a6e005cd

URL: https://github.com/llvm/llvm-project/commit/85e4ee15d32ae0344755d11d4ca90a15a6e005cd
DIFF: https://github.com/llvm/llvm-project/commit/85e4ee15d32ae0344755d11d4ca90a15a6e005cd.diff

LOG: [SystemZ] Avoid type legalization on structs

In SystemZTTIImpl::getMemoryOpCost, the call to getNumberOfParts will
run type legalization, which can't handle structs. So before that, we
check for an unknown value type and forward to BaseT, just like many
other targets do in this situation.

https://bugzilla.redhat.com/show_bug.cgi?id=2224885

Reviewed By: uweigand

Differential Revision: https://reviews.llvm.org/D156379

Added: 
    llvm/test/Analysis/CostModel/SystemZ/struct-cost-crash.ll

Modified: 
    llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp b/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
index 821efc1b758b4f..abac7a9bfe0a2d 100644
--- a/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
@@ -1152,6 +1152,11 @@ InstructionCost SystemZTTIImpl::getMemoryOpCost(unsigned Opcode, Type *Src,
     }
   }
 
+  // Type legalization (via getNumberOfParts) can't handle structs
+  if (TLI->getValueType(DL, Src, true) == MVT::Other)
+    return BaseT::getMemoryOpCost(Opcode, Src, Alignment, AddressSpace,
+                                  CostKind);
+
   unsigned NumOps =
     (Src->isVectorTy() ? getNumVectorRegs(Src) : getNumberOfParts(Src));
 

diff  --git a/llvm/test/Analysis/CostModel/SystemZ/struct-cost-crash.ll b/llvm/test/Analysis/CostModel/SystemZ/struct-cost-crash.ll
new file mode 100644
index 00000000000000..bad23baff2d1c2
--- /dev/null
+++ b/llvm/test/Analysis/CostModel/SystemZ/struct-cost-crash.ll
@@ -0,0 +1,25 @@
+; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 2
+; RUN: opt -passes="print<cost-model>" 2>&1 -disable-output < %s | FileCheck %s
+;
+; Check that SystemZTTIImpl::getMemoryOpCost doesn't try to legalize structs,
+; which was failing llvm_unreachable in MVT::getVT.
+
+target datalayout = "E-m:e-i1:8:16-i8:8:16-i64:64-f128:64-v128:64-a:8:16-n32:64"
+target triple = "s390x-unknown-linux-gnu"
+
+declare { i64, i32 } @bar()
+
+define i8 @foo() {
+; CHECK-LABEL: 'foo'
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: br label %1
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %2 = call { i64, i32 } @bar()
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: store { i64, i32 } %2, ptr inttoptr (i64 16 to ptr), align 16
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: br label %1
+;
+  br label %1
+
+1:                                                ; preds = %1, %0
+  %2 = call { i64, i32 } @bar()
+  store { i64, i32 } %2, ptr inttoptr (i64 16 to ptr), align 16
+  br label %1
+}