[SystemZ] Don't drop MO flags in foldMemoryOperandImpl()

The def operand of the new LG/LD should have the old def operands
flags and subreg index.

New test: test/CodeGen/SystemZ/fold-memory-op-impl.ll

Review: Ulrich Weigand
llvm-svn: 298341

2 files changed, 134 insertions, 5 deletions

diff --git a/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp b/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp
index a1ef3530f90..e139d98c0bf 100644
--- a/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp
@@ -1140,12 +1140,12 @@ MachineInstr *SystemZInstrInfo::foldMemoryOperandImpl(
     // destination register instead.
     if (OpNum == 1) {
       unsigned LoadOpcode = Op0IsGPR ? SystemZ::LG : SystemZ::LD;
-      unsigned Dest = MI.getOperand(0).getReg();
       return BuildMI(*InsertPt->getParent(), InsertPt, MI.getDebugLoc(),
-                     get(LoadOpcode), Dest)
-          .addFrameIndex(FrameIndex)
-          .addImm(0)
-          .addReg(0);
+                     get(LoadOpcode))
+        .add(MI.getOperand(0))
+        .addFrameIndex(FrameIndex)
+        .addImm(0)
+        .addReg(0);
     }
   }
 
diff --git a/llvm/test/CodeGen/SystemZ/fold-memory-op-impl.ll b/llvm/test/CodeGen/SystemZ/fold-memory-op-impl.ll
new file mode 100644
index 00000000000..dda4df90d1b
--- /dev/null
+++ b/llvm/test/CodeGen/SystemZ/fold-memory-op-impl.ll
@@ -0,0 +1,129 @@
+; RUN: llc < %s -mtriple=s390x-linux-gnu -mcpu=z13 -verify-machineinstrs | FileCheck %s
+;
+; Test that foldMemoryOperandImpl() doesn't drop subreg / read-undef flags.
+
+
+define void @fun_llvm_stress_reduced(i8*, i32*, i64*, i64, i8) {
+; CHECK: .text
+BB:
+  %A4 = alloca <4 x i64>
+  %A1 = alloca <8 x i1>
+  %E6 = extractelement <4 x i1> undef, i32 3
+  %L23 = load i8, i8* %0
+  %B27 = fmul double 0x59A989483BA7E0C6, undef
+  %L30 = load i16, i16* undef
+  store i16 -11933, i16* undef
+  %L46 = load i16, i16* undef
+  %L61 = load i16, i16* undef
+  %Sl74 = select i1 undef, i1 undef, i1 true
+  br label %CF846
+
+CF846:                                            ; preds = %CF877, %BB
+  %I86 = insertelement <4 x i1> undef, i1 undef, i32 0
+  %Cmp89 = icmp ne i64 undef, %3
+  %L90 = load i16, i16* undef
+  %Shuff92 = shufflevector <4 x i16> zeroinitializer, <4 x i16> zeroinitializer, <4 x i32> <i32 0, i32 2, i32 undef, i32 6>
+  br label %CF877
+
+CF877:                                            ; preds = %CF846
+  store i16 %L61, i16* undef
+  %Cmp110 = icmp eq i16 %L61, undef
+  br i1 %Cmp110, label %CF846, label %CF862
+
+CF862:                                            ; preds = %CF877
+  %I114 = insertelement <4 x i64> zeroinitializer, i64 0, i32 0
+  %B115 = shl <4 x i64> zeroinitializer, %I114
+  %Sl124 = select i1 true, <8 x i1>* %A1, <8 x i1>* %A1
+  %B130 = frem double %B27, 0x59A989483BA7E0C6
+  %E143 = extractelement <4 x i64> %B115, i32 1
+  %Sl148 = select i1 %Cmp89, <1 x i32> undef, <1 x i32> zeroinitializer
+  br label %CF855
+
+CF855:                                            ; preds = %CF855, %CF862
+  %Sl171 = select i1 %Sl74, i1 %E6, i1 undef
+  br i1 %Sl171, label %CF855, label %CF874
+
+CF874:                                            ; preds = %CF855
+  %PC186 = bitcast i32* %1 to i16*
+  %L196 = load i16, i16* undef
+  %B207 = or i8 %4, %L23
+  %L211 = load <8 x i1>, <8 x i1>* %Sl124
+  %B215 = fdiv double 0x8421A9C0D21F6D3E, %B130
+  %L218 = load i16, i16* %PC186
+  %Sl223 = select i1 %Sl171, <4 x i1> %I86, <4 x i1> undef
+  br label %CF826
+
+CF826:                                            ; preds = %CF866, %CF910, %CF874
+  %B245 = ashr i16 -11933, %L46
+  br label %CF910
+
+CF910:                                            ; preds = %CF826
+  %L257 = load i8, i8* %0
+  %BC262 = bitcast i64 %E143 to double
+  store i16 %L196, i16* %PC186
+  %E266 = extractelement <4 x i16> %Shuff92, i32 0
+  %Sl271 = select i1 %Cmp89, i1 %Cmp89, i1 %Cmp110
+  br i1 %Sl271, label %CF826, label %CF866
+
+CF866:                                            ; preds = %CF910
+  store i64 %E143, i64* %2
+  %I276 = insertelement <4 x double> undef, double %BC262, i32 3
+  %L281 = load <8 x i1>, <8 x i1>* %Sl124
+  %E282 = extractelement <4 x i1> zeroinitializer, i32 2
+  br i1 %E282, label %CF826, label %CF848
+
+CF848:                                            ; preds = %CF866
+  %Cmp288 = fcmp olt <4 x double> undef, %I276
+  %FC294 = fptosi double undef to i16
+  %Cmp296 = icmp ule i16 %FC294, %B245
+  store i16 %L218, i16* undef
+  store i8 %L23, i8* %0
+  %E320 = extractelement <4 x i1> %Sl223, i32 1
+  %PC337 = bitcast <8 x i1>* %Sl124 to i1*
+  %Cmp345 = icmp uge <1 x i32> undef, %Sl148
+  store i16 %L196, i16* %PC186
+  br label %CF893
+
+CF893:                                            ; preds = %CF893, %CF848
+  %Cmp361 = fcmp uge float undef, undef
+  br i1 %Cmp361, label %CF893, label %CF906
+
+CF906:                                            ; preds = %CF893
+  store i16 -11933, i16* undef
+  %Shuff379 = shufflevector <1 x i1> undef, <1 x i1> %Cmp345, <1 x i32> <i32 1>
+  br label %CF850
+
+CF850:                                            ; preds = %CF850, %CF906
+  br i1 undef, label %CF850, label %CF925
+
+CF925:                                            ; preds = %CF850
+  store i16 %E266, i16* %PC186
+  %Cmp413 = icmp ugt i8 %L257, undef
+  store i16 %L30, i16* %PC186
+  %Sl420 = select i1 %Sl171, <8 x i1> undef, <8 x i1> %L281
+  store i16 %L90, i16* undef
+  %FC469 = uitofp i1 %Cmp296 to float
+  store i1 %Cmp413, i1* %PC337
+  br label %CF833
+
+CF833:                                            ; preds = %CF833, %CF925
+  store i8 %B207, i8* %0
+  %E509 = extractelement <8 x i1> %L211, i32 7
+  br i1 %E509, label %CF833, label %CF882
+
+CF882:                                            ; preds = %CF833
+  store i1 %Sl271, i1* %PC337
+  br label %CF852
+
+CF852:                                            ; preds = %CF896, %CF882
+  store i1 %Sl74, i1* %PC337
+  br label %CF896
+
+CF896:                                            ; preds = %CF852
+  %E576 = extractelement <4 x i1> %Cmp288, i32 3
+  br i1 %E576, label %CF852, label %CF890
+
+CF890:                                            ; preds = %CF896
+  %Sl581 = select i1 undef, float undef, float %FC469
+  unreachable
+}