[llvm] r368300 - [RISCV] Minimal stack realignment support

Sam Elliott via llvm-commits llvm-commits at lists.llvm.org
Thu Aug 8 07:40:54 PDT 2019


Author: lenary
Date: Thu Aug  8 07:40:54 2019
New Revision: 368300

URL: http://llvm.org/viewvc/llvm-project?rev=368300&view=rev
Log:
[RISCV] Minimal stack realignment support

Summary:
Currently the RISC-V backend does not realign the stack. This can be an issue even for the RV32I/RV64I ABIs (where the stack is 16-byte aligned), though is rare. It will be much more comment with RV32E (though the alignment requirements for common data types remain under-documented...).

This patch adds minimal support for stack realignment. It should cope with large realignments. It will error out if the stack needs realignment and variable sized objects are present.

It feels like a lot of the code like getFrameIndexReference and determineFrameLayout could be refactored somehow, as right now it feels fiddly and brittle. We also seem to allocate a lot more memory than GCC does for equivalent C code.

Reviewers: asb

Reviewed By: asb

Subscribers: wwei, jrtc27, s.egerton, MaskRay, Jim, lenary, hiraditya, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, kito-cheng, shiva0217, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei, psnobl, benna, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62007

Added:
    llvm/trunk/test/CodeGen/RISCV/stack-realignment-unsupported.ll
    llvm/trunk/test/CodeGen/RISCV/stack-realignment.ll
Modified:
    llvm/trunk/lib/Target/RISCV/RISCVFrameLowering.cpp

Modified: llvm/trunk/lib/Target/RISCV/RISCVFrameLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/RISCV/RISCVFrameLowering.cpp?rev=368300&r1=368299&r2=368300&view=diff
==============================================================================
--- llvm/trunk/lib/Target/RISCV/RISCVFrameLowering.cpp (original)
+++ llvm/trunk/lib/Target/RISCV/RISCVFrameLowering.cpp Thu Aug  8 07:40:54 2019
@@ -40,8 +40,16 @@ void RISCVFrameLowering::determineFrameL
   uint64_t FrameSize = MFI.getStackSize();
 
   // Get the alignment.
-  uint64_t StackAlign = RI->needsStackRealignment(MF) ? MFI.getMaxAlignment()
-                                                      : getStackAlignment();
+  unsigned StackAlign = getStackAlignment();
+  if (RI->needsStackRealignment(MF)) {
+    unsigned MaxStackAlign = std::max(StackAlign, MFI.getMaxAlignment());
+    FrameSize += (MaxStackAlign - StackAlign);
+    StackAlign = MaxStackAlign;
+  }
+
+  // Set Max Call Frame Size
+  uint64_t MaxCallSize = alignTo(MFI.getMaxCallFrameSize(), StackAlign);
+  MFI.setMaxCallFrameSize(MaxCallSize);
 
   // Make sure the frame is aligned.
   FrameSize = alignTo(FrameSize, StackAlign);
@@ -101,6 +109,12 @@ void RISCVFrameLowering::emitPrologue(Ma
   const RISCVInstrInfo *TII = STI.getInstrInfo();
   MachineBasicBlock::iterator MBBI = MBB.begin();
 
+  if (RI->needsStackRealignment(MF) && MFI.hasVarSizedObjects()) {
+    report_fatal_error(
+        "RISC-V backend can't currently handle functions that need stack "
+        "realignment and have variable sized objects");
+  }
+
   unsigned FPReg = getFPReg(STI);
   unsigned SPReg = getSPReg(STI);
 
@@ -158,6 +172,29 @@ void RISCVFrameLowering::emitPrologue(Ma
         nullptr, RI->getDwarfRegNum(FPReg, true), 0));
     BuildMI(MBB, MBBI, DL, TII->get(TargetOpcode::CFI_INSTRUCTION))
         .addCFIIndex(CFIIndex);
+
+    // Realign Stack
+    const RISCVRegisterInfo *RI = STI.getRegisterInfo();
+    if (RI->needsStackRealignment(MF)) {
+      unsigned MaxAlignment = MFI.getMaxAlignment();
+
+      const RISCVInstrInfo *TII = STI.getInstrInfo();
+      if (isInt<12>(-(int)MaxAlignment)) {
+        BuildMI(MBB, MBBI, DL, TII->get(RISCV::ANDI), SPReg)
+            .addReg(SPReg)
+            .addImm(-(int)MaxAlignment);
+      } else {
+        unsigned ShiftAmount = countTrailingZeros(MaxAlignment);
+        unsigned VR =
+            MF.getRegInfo().createVirtualRegister(&RISCV::GPRRegClass);
+        BuildMI(MBB, MBBI, DL, TII->get(RISCV::SRLI), VR)
+            .addReg(SPReg)
+            .addImm(ShiftAmount);
+        BuildMI(MBB, MBBI, DL, TII->get(RISCV::SLLI), SPReg)
+            .addReg(VR)
+            .addImm(ShiftAmount);
+      }
+    }
   }
 }
 
@@ -257,6 +294,13 @@ int RISCVFrameLowering::getFrameIndexRef
   if (FI >= MinCSFI && FI <= MaxCSFI) {
     FrameReg = RISCV::X2;
     Offset += MF.getFrameInfo().getStackSize();
+  } else if (RI->needsStackRealignment(MF)) {
+    assert(!MFI.hasVarSizedObjects() &&
+           "Unexpected combination of stack realignment and varsized objects");
+    // If the stack was realigned, the frame pointer is set in order to allow
+    // SP to be restored, but we still access stack objects using SP.
+    FrameReg = RISCV::X2;
+    Offset += MF.getFrameInfo().getStackSize();
   } else {
     FrameReg = RI->getFrameRegister(MF);
     if (hasFP(MF))

Added: llvm/trunk/test/CodeGen/RISCV/stack-realignment-unsupported.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/RISCV/stack-realignment-unsupported.ll?rev=368300&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/RISCV/stack-realignment-unsupported.ll (added)
+++ llvm/trunk/test/CodeGen/RISCV/stack-realignment-unsupported.ll Thu Aug  8 07:40:54 2019
@@ -0,0 +1,13 @@
+; RUN: not llc -mtriple=riscv32 < %s 2>&1 | FileCheck %s
+; RUN: not llc -mtriple=riscv64 < %s 2>&1 | FileCheck %s
+
+; CHECK: LLVM ERROR: RISC-V backend can't currently handle functions that need stack realignment and have variable sized objects
+
+declare void @callee(i8*, i32*)
+
+define void @caller(i32 %n) nounwind {
+  %1 = alloca i8, i32 %n
+  %2 = alloca i32, align 64
+  call void @callee(i8* %1, i32 *%2)
+  ret void
+}

Added: llvm/trunk/test/CodeGen/RISCV/stack-realignment.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/RISCV/stack-realignment.ll?rev=368300&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/RISCV/stack-realignment.ll (added)
+++ llvm/trunk/test/CodeGen/RISCV/stack-realignment.ll Thu Aug  8 07:40:54 2019
@@ -0,0 +1,627 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=riscv32 -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s -check-prefix=RV32I
+; RUN: llc -mtriple=riscv64 -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s -check-prefix=RV64I
+
+declare void @callee(i8*)
+
+define void @caller32() nounwind {
+; RV32I-LABEL: caller32:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    addi sp, sp, -64
+; RV32I-NEXT:    sw ra, 60(sp)
+; RV32I-NEXT:    sw s0, 56(sp)
+; RV32I-NEXT:    addi s0, sp, 64
+; RV32I-NEXT:    andi sp, sp, -32
+; RV32I-NEXT:    addi a0, sp, 32
+; RV32I-NEXT:    call callee
+; RV32I-NEXT:    addi sp, s0, -64
+; RV32I-NEXT:    lw s0, 56(sp)
+; RV32I-NEXT:    lw ra, 60(sp)
+; RV32I-NEXT:    addi sp, sp, 64
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: caller32:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    addi sp, sp, -64
+; RV64I-NEXT:    sd ra, 56(sp)
+; RV64I-NEXT:    sd s0, 48(sp)
+; RV64I-NEXT:    addi s0, sp, 64
+; RV64I-NEXT:    andi sp, sp, -32
+; RV64I-NEXT:    addi a0, sp, 32
+; RV64I-NEXT:    call callee
+; RV64I-NEXT:    addi sp, s0, -64
+; RV64I-NEXT:    ld s0, 48(sp)
+; RV64I-NEXT:    ld ra, 56(sp)
+; RV64I-NEXT:    addi sp, sp, 64
+; RV64I-NEXT:    ret
+  %1 = alloca i8, align 32
+  call void @callee(i8* %1)
+  ret void
+}
+
+define void @caller_no_realign32() nounwind "no-realign-stack" {
+; RV32I-LABEL: caller_no_realign32:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    addi sp, sp, -16
+; RV32I-NEXT:    sw ra, 12(sp)
+; RV32I-NEXT:    mv a0, sp
+; RV32I-NEXT:    call callee
+; RV32I-NEXT:    lw ra, 12(sp)
+; RV32I-NEXT:    addi sp, sp, 16
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: caller_no_realign32:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    addi sp, sp, -16
+; RV64I-NEXT:    sd ra, 8(sp)
+; RV64I-NEXT:    mv a0, sp
+; RV64I-NEXT:    call callee
+; RV64I-NEXT:    ld ra, 8(sp)
+; RV64I-NEXT:    addi sp, sp, 16
+; RV64I-NEXT:    ret
+  %1 = alloca i8, align 32
+  call void @callee(i8* %1)
+  ret void
+}
+
+define void @caller64() nounwind {
+; RV32I-LABEL: caller64:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    addi sp, sp, -128
+; RV32I-NEXT:    sw ra, 124(sp)
+; RV32I-NEXT:    sw s0, 120(sp)
+; RV32I-NEXT:    addi s0, sp, 128
+; RV32I-NEXT:    andi sp, sp, -64
+; RV32I-NEXT:    addi a0, sp, 64
+; RV32I-NEXT:    call callee
+; RV32I-NEXT:    addi sp, s0, -128
+; RV32I-NEXT:    lw s0, 120(sp)
+; RV32I-NEXT:    lw ra, 124(sp)
+; RV32I-NEXT:    addi sp, sp, 128
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: caller64:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    addi sp, sp, -128
+; RV64I-NEXT:    sd ra, 120(sp)
+; RV64I-NEXT:    sd s0, 112(sp)
+; RV64I-NEXT:    addi s0, sp, 128
+; RV64I-NEXT:    andi sp, sp, -64
+; RV64I-NEXT:    addi a0, sp, 64
+; RV64I-NEXT:    call callee
+; RV64I-NEXT:    addi sp, s0, -128
+; RV64I-NEXT:    ld s0, 112(sp)
+; RV64I-NEXT:    ld ra, 120(sp)
+; RV64I-NEXT:    addi sp, sp, 128
+; RV64I-NEXT:    ret
+  %1 = alloca i8, align 64
+  call void @callee(i8* %1)
+  ret void
+}
+
+define void @caller_no_realign64() nounwind "no-realign-stack" {
+; RV32I-LABEL: caller_no_realign64:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    addi sp, sp, -16
+; RV32I-NEXT:    sw ra, 12(sp)
+; RV32I-NEXT:    mv a0, sp
+; RV32I-NEXT:    call callee
+; RV32I-NEXT:    lw ra, 12(sp)
+; RV32I-NEXT:    addi sp, sp, 16
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: caller_no_realign64:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    addi sp, sp, -16
+; RV64I-NEXT:    sd ra, 8(sp)
+; RV64I-NEXT:    mv a0, sp
+; RV64I-NEXT:    call callee
+; RV64I-NEXT:    ld ra, 8(sp)
+; RV64I-NEXT:    addi sp, sp, 16
+; RV64I-NEXT:    ret
+  %1 = alloca i8, align 64
+  call void @callee(i8* %1)
+  ret void
+}
+
+define void @caller128() nounwind {
+; RV32I-LABEL: caller128:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    addi sp, sp, -256
+; RV32I-NEXT:    sw ra, 252(sp)
+; RV32I-NEXT:    sw s0, 248(sp)
+; RV32I-NEXT:    addi s0, sp, 256
+; RV32I-NEXT:    andi sp, sp, -128
+; RV32I-NEXT:    addi a0, sp, 128
+; RV32I-NEXT:    call callee
+; RV32I-NEXT:    addi sp, s0, -256
+; RV32I-NEXT:    lw s0, 248(sp)
+; RV32I-NEXT:    lw ra, 252(sp)
+; RV32I-NEXT:    addi sp, sp, 256
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: caller128:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    addi sp, sp, -256
+; RV64I-NEXT:    sd ra, 248(sp)
+; RV64I-NEXT:    sd s0, 240(sp)
+; RV64I-NEXT:    addi s0, sp, 256
+; RV64I-NEXT:    andi sp, sp, -128
+; RV64I-NEXT:    addi a0, sp, 128
+; RV64I-NEXT:    call callee
+; RV64I-NEXT:    addi sp, s0, -256
+; RV64I-NEXT:    ld s0, 240(sp)
+; RV64I-NEXT:    ld ra, 248(sp)
+; RV64I-NEXT:    addi sp, sp, 256
+; RV64I-NEXT:    ret
+  %1 = alloca i8, align 128
+  call void @callee(i8* %1)
+  ret void
+}
+
+define void @caller_no_realign128() nounwind "no-realign-stack" {
+; RV32I-LABEL: caller_no_realign128:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    addi sp, sp, -16
+; RV32I-NEXT:    sw ra, 12(sp)
+; RV32I-NEXT:    mv a0, sp
+; RV32I-NEXT:    call callee
+; RV32I-NEXT:    lw ra, 12(sp)
+; RV32I-NEXT:    addi sp, sp, 16
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: caller_no_realign128:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    addi sp, sp, -16
+; RV64I-NEXT:    sd ra, 8(sp)
+; RV64I-NEXT:    mv a0, sp
+; RV64I-NEXT:    call callee
+; RV64I-NEXT:    ld ra, 8(sp)
+; RV64I-NEXT:    addi sp, sp, 16
+; RV64I-NEXT:    ret
+  %1 = alloca i8, align 128
+  call void @callee(i8* %1)
+  ret void
+}
+
+define void @caller256() nounwind {
+; RV32I-LABEL: caller256:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    addi sp, sp, -512
+; RV32I-NEXT:    sw ra, 508(sp)
+; RV32I-NEXT:    sw s0, 504(sp)
+; RV32I-NEXT:    addi s0, sp, 512
+; RV32I-NEXT:    andi sp, sp, -256
+; RV32I-NEXT:    addi a0, sp, 256
+; RV32I-NEXT:    call callee
+; RV32I-NEXT:    addi sp, s0, -512
+; RV32I-NEXT:    lw s0, 504(sp)
+; RV32I-NEXT:    lw ra, 508(sp)
+; RV32I-NEXT:    addi sp, sp, 512
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: caller256:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    addi sp, sp, -512
+; RV64I-NEXT:    sd ra, 504(sp)
+; RV64I-NEXT:    sd s0, 496(sp)
+; RV64I-NEXT:    addi s0, sp, 512
+; RV64I-NEXT:    andi sp, sp, -256
+; RV64I-NEXT:    addi a0, sp, 256
+; RV64I-NEXT:    call callee
+; RV64I-NEXT:    addi sp, s0, -512
+; RV64I-NEXT:    ld s0, 496(sp)
+; RV64I-NEXT:    ld ra, 504(sp)
+; RV64I-NEXT:    addi sp, sp, 512
+; RV64I-NEXT:    ret
+  %1 = alloca i8, align 256
+  call void @callee(i8* %1)
+  ret void
+}
+
+define void @caller_no_realign256() nounwind "no-realign-stack" {
+; RV32I-LABEL: caller_no_realign256:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    addi sp, sp, -16
+; RV32I-NEXT:    sw ra, 12(sp)
+; RV32I-NEXT:    mv a0, sp
+; RV32I-NEXT:    call callee
+; RV32I-NEXT:    lw ra, 12(sp)
+; RV32I-NEXT:    addi sp, sp, 16
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: caller_no_realign256:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    addi sp, sp, -16
+; RV64I-NEXT:    sd ra, 8(sp)
+; RV64I-NEXT:    mv a0, sp
+; RV64I-NEXT:    call callee
+; RV64I-NEXT:    ld ra, 8(sp)
+; RV64I-NEXT:    addi sp, sp, 16
+; RV64I-NEXT:    ret
+  %1 = alloca i8, align 256
+  call void @callee(i8* %1)
+  ret void
+}
+
+define void @caller512() nounwind {
+; RV32I-LABEL: caller512:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    addi sp, sp, -1536
+; RV32I-NEXT:    sw ra, 1532(sp)
+; RV32I-NEXT:    sw s0, 1528(sp)
+; RV32I-NEXT:    addi s0, sp, 1536
+; RV32I-NEXT:    andi sp, sp, -512
+; RV32I-NEXT:    addi a0, sp, 1024
+; RV32I-NEXT:    call callee
+; RV32I-NEXT:    addi sp, s0, -1536
+; RV32I-NEXT:    lw s0, 1528(sp)
+; RV32I-NEXT:    lw ra, 1532(sp)
+; RV32I-NEXT:    addi sp, sp, 1536
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: caller512:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    addi sp, sp, -1536
+; RV64I-NEXT:    sd ra, 1528(sp)
+; RV64I-NEXT:    sd s0, 1520(sp)
+; RV64I-NEXT:    addi s0, sp, 1536
+; RV64I-NEXT:    andi sp, sp, -512
+; RV64I-NEXT:    addi a0, sp, 1024
+; RV64I-NEXT:    call callee
+; RV64I-NEXT:    addi sp, s0, -1536
+; RV64I-NEXT:    ld s0, 1520(sp)
+; RV64I-NEXT:    ld ra, 1528(sp)
+; RV64I-NEXT:    addi sp, sp, 1536
+; RV64I-NEXT:    ret
+  %1 = alloca i8, align 512
+  call void @callee(i8* %1)
+  ret void
+}
+
+define void @caller_no_realign512() nounwind "no-realign-stack" {
+; RV32I-LABEL: caller_no_realign512:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    addi sp, sp, -16
+; RV32I-NEXT:    sw ra, 12(sp)
+; RV32I-NEXT:    mv a0, sp
+; RV32I-NEXT:    call callee
+; RV32I-NEXT:    lw ra, 12(sp)
+; RV32I-NEXT:    addi sp, sp, 16
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: caller_no_realign512:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    addi sp, sp, -16
+; RV64I-NEXT:    sd ra, 8(sp)
+; RV64I-NEXT:    mv a0, sp
+; RV64I-NEXT:    call callee
+; RV64I-NEXT:    ld ra, 8(sp)
+; RV64I-NEXT:    addi sp, sp, 16
+; RV64I-NEXT:    ret
+  %1 = alloca i8, align 512
+  call void @callee(i8* %1)
+  ret void
+}
+
+define void @caller1024() nounwind {
+; RV32I-LABEL: caller1024:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    lui a0, 1
+; RV32I-NEXT:    addi a0, a0, -1024
+; RV32I-NEXT:    sub sp, sp, a0
+; RV32I-NEXT:    lui a0, 1
+; RV32I-NEXT:    addi a0, a0, -1028
+; RV32I-NEXT:    add a0, sp, a0
+; RV32I-NEXT:    sw ra, 0(a0)
+; RV32I-NEXT:    lui a0, 1
+; RV32I-NEXT:    addi a0, a0, -1032
+; RV32I-NEXT:    add a0, sp, a0
+; RV32I-NEXT:    sw s0, 0(a0)
+; RV32I-NEXT:    lui a0, 1
+; RV32I-NEXT:    addi a0, a0, -1024
+; RV32I-NEXT:    add s0, sp, a0
+; RV32I-NEXT:    andi sp, sp, -1024
+; RV32I-NEXT:    lui a0, 1
+; RV32I-NEXT:    addi a0, a0, -2048
+; RV32I-NEXT:    add a0, sp, a0
+; RV32I-NEXT:    mv a0, a0
+; RV32I-NEXT:    call callee
+; RV32I-NEXT:    lui a0, 1
+; RV32I-NEXT:    addi a0, a0, -1024
+; RV32I-NEXT:    sub sp, s0, a0
+; RV32I-NEXT:    lui a0, 1
+; RV32I-NEXT:    addi a0, a0, -1032
+; RV32I-NEXT:    add a0, sp, a0
+; RV32I-NEXT:    lw s0, 0(a0)
+; RV32I-NEXT:    lui a0, 1
+; RV32I-NEXT:    addi a0, a0, -1028
+; RV32I-NEXT:    add a0, sp, a0
+; RV32I-NEXT:    lw ra, 0(a0)
+; RV32I-NEXT:    lui a0, 1
+; RV32I-NEXT:    addi a0, a0, -1024
+; RV32I-NEXT:    add sp, sp, a0
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: caller1024:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    lui a0, 1
+; RV64I-NEXT:    addi a0, a0, -1024
+; RV64I-NEXT:    sub sp, sp, a0
+; RV64I-NEXT:    lui a0, 1
+; RV64I-NEXT:    addi a0, a0, -1032
+; RV64I-NEXT:    add a0, sp, a0
+; RV64I-NEXT:    sd ra, 0(a0)
+; RV64I-NEXT:    lui a0, 1
+; RV64I-NEXT:    addi a0, a0, -1040
+; RV64I-NEXT:    add a0, sp, a0
+; RV64I-NEXT:    sd s0, 0(a0)
+; RV64I-NEXT:    lui a0, 1
+; RV64I-NEXT:    addi a0, a0, -1024
+; RV64I-NEXT:    add s0, sp, a0
+; RV64I-NEXT:    andi sp, sp, -1024
+; RV64I-NEXT:    lui a0, 1
+; RV64I-NEXT:    addi a0, a0, -2048
+; RV64I-NEXT:    add a0, sp, a0
+; RV64I-NEXT:    mv a0, a0
+; RV64I-NEXT:    call callee
+; RV64I-NEXT:    lui a0, 1
+; RV64I-NEXT:    addi a0, a0, -1024
+; RV64I-NEXT:    sub sp, s0, a0
+; RV64I-NEXT:    lui a0, 1
+; RV64I-NEXT:    addi a0, a0, -1040
+; RV64I-NEXT:    add a0, sp, a0
+; RV64I-NEXT:    ld s0, 0(a0)
+; RV64I-NEXT:    lui a0, 1
+; RV64I-NEXT:    addi a0, a0, -1032
+; RV64I-NEXT:    add a0, sp, a0
+; RV64I-NEXT:    ld ra, 0(a0)
+; RV64I-NEXT:    lui a0, 1
+; RV64I-NEXT:    addi a0, a0, -1024
+; RV64I-NEXT:    add sp, sp, a0
+; RV64I-NEXT:    ret
+  %1 = alloca i8, align 1024
+  call void @callee(i8* %1)
+  ret void
+}
+
+define void @caller_no_realign1024() nounwind "no-realign-stack" {
+; RV32I-LABEL: caller_no_realign1024:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    addi sp, sp, -16
+; RV32I-NEXT:    sw ra, 12(sp)
+; RV32I-NEXT:    mv a0, sp
+; RV32I-NEXT:    call callee
+; RV32I-NEXT:    lw ra, 12(sp)
+; RV32I-NEXT:    addi sp, sp, 16
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: caller_no_realign1024:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    addi sp, sp, -16
+; RV64I-NEXT:    sd ra, 8(sp)
+; RV64I-NEXT:    mv a0, sp
+; RV64I-NEXT:    call callee
+; RV64I-NEXT:    ld ra, 8(sp)
+; RV64I-NEXT:    addi sp, sp, 16
+; RV64I-NEXT:    ret
+  %1 = alloca i8, align 1024
+  call void @callee(i8* %1)
+  ret void
+}
+
+define void @caller2048() nounwind {
+; RV32I-LABEL: caller2048:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    lui a0, 2
+; RV32I-NEXT:    addi a0, a0, -2048
+; RV32I-NEXT:    sub sp, sp, a0
+; RV32I-NEXT:    lui a0, 1
+; RV32I-NEXT:    addi a0, a0, 2044
+; RV32I-NEXT:    add a0, sp, a0
+; RV32I-NEXT:    sw ra, 0(a0)
+; RV32I-NEXT:    lui a0, 1
+; RV32I-NEXT:    addi a0, a0, 2040
+; RV32I-NEXT:    add a0, sp, a0
+; RV32I-NEXT:    sw s0, 0(a0)
+; RV32I-NEXT:    lui a0, 2
+; RV32I-NEXT:    addi a0, a0, -2048
+; RV32I-NEXT:    add s0, sp, a0
+; RV32I-NEXT:    andi sp, sp, -2048
+; RV32I-NEXT:    lui a0, 1
+; RV32I-NEXT:    mv a0, a0
+; RV32I-NEXT:    add a0, sp, a0
+; RV32I-NEXT:    mv a0, a0
+; RV32I-NEXT:    call callee
+; RV32I-NEXT:    lui a0, 2
+; RV32I-NEXT:    addi a0, a0, -2048
+; RV32I-NEXT:    sub sp, s0, a0
+; RV32I-NEXT:    lui a0, 1
+; RV32I-NEXT:    addi a0, a0, 2040
+; RV32I-NEXT:    add a0, sp, a0
+; RV32I-NEXT:    lw s0, 0(a0)
+; RV32I-NEXT:    lui a0, 1
+; RV32I-NEXT:    addi a0, a0, 2044
+; RV32I-NEXT:    add a0, sp, a0
+; RV32I-NEXT:    lw ra, 0(a0)
+; RV32I-NEXT:    lui a0, 2
+; RV32I-NEXT:    addi a0, a0, -2048
+; RV32I-NEXT:    add sp, sp, a0
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: caller2048:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    lui a0, 2
+; RV64I-NEXT:    addi a0, a0, -2048
+; RV64I-NEXT:    sub sp, sp, a0
+; RV64I-NEXT:    lui a0, 1
+; RV64I-NEXT:    addi a0, a0, 2040
+; RV64I-NEXT:    add a0, sp, a0
+; RV64I-NEXT:    sd ra, 0(a0)
+; RV64I-NEXT:    lui a0, 1
+; RV64I-NEXT:    addi a0, a0, 2032
+; RV64I-NEXT:    add a0, sp, a0
+; RV64I-NEXT:    sd s0, 0(a0)
+; RV64I-NEXT:    lui a0, 2
+; RV64I-NEXT:    addi a0, a0, -2048
+; RV64I-NEXT:    add s0, sp, a0
+; RV64I-NEXT:    andi sp, sp, -2048
+; RV64I-NEXT:    lui a0, 1
+; RV64I-NEXT:    mv a0, a0
+; RV64I-NEXT:    add a0, sp, a0
+; RV64I-NEXT:    mv a0, a0
+; RV64I-NEXT:    call callee
+; RV64I-NEXT:    lui a0, 2
+; RV64I-NEXT:    addi a0, a0, -2048
+; RV64I-NEXT:    sub sp, s0, a0
+; RV64I-NEXT:    lui a0, 1
+; RV64I-NEXT:    addi a0, a0, 2032
+; RV64I-NEXT:    add a0, sp, a0
+; RV64I-NEXT:    ld s0, 0(a0)
+; RV64I-NEXT:    lui a0, 1
+; RV64I-NEXT:    addi a0, a0, 2040
+; RV64I-NEXT:    add a0, sp, a0
+; RV64I-NEXT:    ld ra, 0(a0)
+; RV64I-NEXT:    lui a0, 2
+; RV64I-NEXT:    addi a0, a0, -2048
+; RV64I-NEXT:    add sp, sp, a0
+; RV64I-NEXT:    ret
+  %1 = alloca i8, align 2048
+  call void @callee(i8* %1)
+  ret void
+}
+
+define void @caller_no_realign2048() nounwind "no-realign-stack" {
+; RV32I-LABEL: caller_no_realign2048:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    addi sp, sp, -16
+; RV32I-NEXT:    sw ra, 12(sp)
+; RV32I-NEXT:    mv a0, sp
+; RV32I-NEXT:    call callee
+; RV32I-NEXT:    lw ra, 12(sp)
+; RV32I-NEXT:    addi sp, sp, 16
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: caller_no_realign2048:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    addi sp, sp, -16
+; RV64I-NEXT:    sd ra, 8(sp)
+; RV64I-NEXT:    mv a0, sp
+; RV64I-NEXT:    call callee
+; RV64I-NEXT:    ld ra, 8(sp)
+; RV64I-NEXT:    addi sp, sp, 16
+; RV64I-NEXT:    ret
+  %1 = alloca i8, align 2048
+  call void @callee(i8* %1)
+  ret void
+}
+
+define void @caller4096() nounwind {
+; RV32I-LABEL: caller4096:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    lui a0, 3
+; RV32I-NEXT:    mv a0, a0
+; RV32I-NEXT:    sub sp, sp, a0
+; RV32I-NEXT:    lui a0, 3
+; RV32I-NEXT:    addi a0, a0, -4
+; RV32I-NEXT:    add a0, sp, a0
+; RV32I-NEXT:    sw ra, 0(a0)
+; RV32I-NEXT:    lui a0, 3
+; RV32I-NEXT:    addi a0, a0, -8
+; RV32I-NEXT:    add a0, sp, a0
+; RV32I-NEXT:    sw s0, 0(a0)
+; RV32I-NEXT:    lui a0, 3
+; RV32I-NEXT:    mv a0, a0
+; RV32I-NEXT:    add s0, sp, a0
+; RV32I-NEXT:    srli a0, sp, 12
+; RV32I-NEXT:    slli sp, a0, 12
+; RV32I-NEXT:    lui a0, 2
+; RV32I-NEXT:    mv a0, a0
+; RV32I-NEXT:    add a0, sp, a0
+; RV32I-NEXT:    mv a0, a0
+; RV32I-NEXT:    call callee
+; RV32I-NEXT:    lui a0, 3
+; RV32I-NEXT:    mv a0, a0
+; RV32I-NEXT:    sub sp, s0, a0
+; RV32I-NEXT:    lui a0, 3
+; RV32I-NEXT:    addi a0, a0, -8
+; RV32I-NEXT:    add a0, sp, a0
+; RV32I-NEXT:    lw s0, 0(a0)
+; RV32I-NEXT:    lui a0, 3
+; RV32I-NEXT:    addi a0, a0, -4
+; RV32I-NEXT:    add a0, sp, a0
+; RV32I-NEXT:    lw ra, 0(a0)
+; RV32I-NEXT:    lui a0, 3
+; RV32I-NEXT:    mv a0, a0
+; RV32I-NEXT:    add sp, sp, a0
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: caller4096:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    lui a0, 3
+; RV64I-NEXT:    mv a0, a0
+; RV64I-NEXT:    sub sp, sp, a0
+; RV64I-NEXT:    lui a0, 3
+; RV64I-NEXT:    addi a0, a0, -8
+; RV64I-NEXT:    add a0, sp, a0
+; RV64I-NEXT:    sd ra, 0(a0)
+; RV64I-NEXT:    lui a0, 3
+; RV64I-NEXT:    addi a0, a0, -16
+; RV64I-NEXT:    add a0, sp, a0
+; RV64I-NEXT:    sd s0, 0(a0)
+; RV64I-NEXT:    lui a0, 3
+; RV64I-NEXT:    mv a0, a0
+; RV64I-NEXT:    add s0, sp, a0
+; RV64I-NEXT:    srli a0, sp, 12
+; RV64I-NEXT:    slli sp, a0, 12
+; RV64I-NEXT:    lui a0, 2
+; RV64I-NEXT:    mv a0, a0
+; RV64I-NEXT:    add a0, sp, a0
+; RV64I-NEXT:    mv a0, a0
+; RV64I-NEXT:    call callee
+; RV64I-NEXT:    lui a0, 3
+; RV64I-NEXT:    mv a0, a0
+; RV64I-NEXT:    sub sp, s0, a0
+; RV64I-NEXT:    lui a0, 3
+; RV64I-NEXT:    addi a0, a0, -16
+; RV64I-NEXT:    add a0, sp, a0
+; RV64I-NEXT:    ld s0, 0(a0)
+; RV64I-NEXT:    lui a0, 3
+; RV64I-NEXT:    addi a0, a0, -8
+; RV64I-NEXT:    add a0, sp, a0
+; RV64I-NEXT:    ld ra, 0(a0)
+; RV64I-NEXT:    lui a0, 3
+; RV64I-NEXT:    mv a0, a0
+; RV64I-NEXT:    add sp, sp, a0
+; RV64I-NEXT:    ret
+  %1 = alloca i8, align 4096
+  call void @callee(i8* %1)
+  ret void
+}
+
+define void @caller_no_realign4096() nounwind "no-realign-stack" {
+; RV32I-LABEL: caller_no_realign4096:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    addi sp, sp, -16
+; RV32I-NEXT:    sw ra, 12(sp)
+; RV32I-NEXT:    mv a0, sp
+; RV32I-NEXT:    call callee
+; RV32I-NEXT:    lw ra, 12(sp)
+; RV32I-NEXT:    addi sp, sp, 16
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: caller_no_realign4096:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    addi sp, sp, -16
+; RV64I-NEXT:    sd ra, 8(sp)
+; RV64I-NEXT:    mv a0, sp
+; RV64I-NEXT:    call callee
+; RV64I-NEXT:    ld ra, 8(sp)
+; RV64I-NEXT:    addi sp, sp, 16
+; RV64I-NEXT:    ret
+  %1 = alloca i8, align 4096
+  call void @callee(i8* %1)
+  ret void
+}




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