ARM: don't add FrameIndex offset for LDMIA (has no immediate)

Previously, when spilling 64-bit paired registers, an LDMIA with both
a FrameIndex and an offset was produced. This kind of instruction
shouldn't exist, and the extra operand was being confused with the
predicate, causing aborts later on.

This removes the invalid 0-offset from the instruction being
produced.

llvm-svn: 179956

2 files changed, 37 insertions, 1 deletions

diff --git a/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp b/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
index 9e68ff44890..7a8077e3f9e 100644
--- a/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
+++ b/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
@@ -978,7 +978,7 @@ loadRegFromStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
       unsigned LdmOpc = AFI->isThumbFunction() ? ARM::t2LDMIA : ARM::LDMIA;
       MachineInstrBuilder MIB =
         AddDefaultPred(BuildMI(MBB, I, DL, get(LdmOpc))
-                    .addFrameIndex(FI).addImm(0).addMemOperand(MMO));
+                    .addFrameIndex(FI).addMemOperand(MMO));
       MIB = AddDReg(MIB, DestReg, ARM::gsub_0, RegState::DefineNoRead, TRI);
       MIB = AddDReg(MIB, DestReg, ARM::gsub_1, RegState::DefineNoRead, TRI);
       if (TargetRegisterInfo::isPhysicalRegister(DestReg))
diff --git a/llvm/test/CodeGen/ARM/gpr-paired-spill.ll b/llvm/test/CodeGen/ARM/gpr-paired-spill.ll
new file mode 100644
index 00000000000..400d69d0d41
--- /dev/null
+++ b/llvm/test/CodeGen/ARM/gpr-paired-spill.ll
@@ -0,0 +1,36 @@
+; RUN: llc -mtriple=armv7-none-linux-gnueabi < %s | FileCheck %s
+
+define void @foo(i64* %addr) {
+  %val1 = tail call i64 asm sideeffect "ldrd $0, ${0:H}, [r0]", "=&r,r"(i64* %addr)
+  %val2 = tail call i64 asm sideeffect "ldrd $0, ${0:H}, [r0]", "=&r,r"(i64* %addr)
+  %val3 = tail call i64 asm sideeffect "ldrd $0, ${0:H}, [r0]", "=&r,r"(i64* %addr)
+  %val4 = tail call i64 asm sideeffect "ldrd $0, ${0:H}, [r0]", "=&r,r"(i64* %addr)
+  %val5 = tail call i64 asm sideeffect "ldrd $0, ${0:H}, [r0]", "=&r,r"(i64* %addr)
+  %val6 = tail call i64 asm sideeffect "ldrd $0, ${0:H}, [r0]", "=&r,r"(i64* %addr)
+  %val7 = tail call i64 asm sideeffect "ldrd $0, ${0:H}, [r0]", "=&r,r"(i64* %addr)
+
+  ; Key point is that enough 64-bit paired GPR values are live that
+  ; one of them has to be spilled. This used to cause an abort because
+  ; an LDMIA was created with both a FrameIndex and an offset, which
+  ; is not allowed.
+
+  ; We also want to ensure the register scavenger is working (i.e. an
+  ; offset from sp can be generated), so we need two spills.
+; CHECK: add [[ADDRREG:[a-z0-9]+]], sp, #{{[0-9]+}}
+; CHECK: stm [[ADDRREG]], {r{{[0-9]+}}, r{{[0-9]+}}}
+; CHECK: stm sp, {r{{[0-9]+}}, r{{[0-9]+}}}
+
+  ; In principle LLVM may have to recalculate the offset. At the moment
+  ; it reuses the original though.
+; CHECK: ldm [[ADDRREG]], {r{{[0-9]+}}, r{{[0-9]+}}}
+; CHECK: ldm sp, {r{{[0-9]+}}, r{{[0-9]+}}}
+
+  store volatile i64 %val1, i64* %addr
+  store volatile i64 %val2, i64* %addr
+  store volatile i64 %val3, i64* %addr
+  store volatile i64 %val4, i64* %addr
+  store volatile i64 %val5, i64* %addr
+  store volatile i64 %val6, i64* %addr
+  store volatile i64 %val7, i64* %addr
+  ret void
+}