Skip to content

Commit

Permalink
[llvm][Mips] Bail on underaligned loads/stores in FastISel.
Browse files Browse the repository at this point in the history
  • Loading branch information
@alexrp
alexrp committed Sep 2, 2024
1 parent 0ba006d commit 1299cc9
Show file tree
Hide file tree
Showing 2 changed files with 131 additions and 8 deletions.
30 changes: 22 additions & 8 deletions llvm/lib/Target/Mips/MipsFastISel.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -881,38 +881,52 @@ bool MipsFastISel::selectLogicalOp(const Instruction *I) {
}

bool MipsFastISel::selectLoad(const Instruction *I) {
const LoadInst *LI = cast<LoadInst>(I);

// Atomic loads need special handling.
if (cast<LoadInst>(I)->isAtomic())
if (LI->isAtomic())
return false;

// Verify we have a legal type before going any further.
MVT VT;
if (!isLoadTypeLegal(I->getType(), VT))
if (!isLoadTypeLegal(LI->getType(), VT))
return false;

// Underaligned loads need special handling.
if (LI->getAlign() < VT.getFixedSizeInBits() / 8 &&
!Subtarget->systemSupportsUnalignedAccess())
return false;

// See if we can handle this address.
Address Addr;
if (!computeAddress(I->getOperand(0), Addr))
if (!computeAddress(LI->getOperand(0), Addr))
return false;

unsigned ResultReg;
if (!emitLoad(VT, ResultReg, Addr))
return false;
updateValueMap(I, ResultReg);
updateValueMap(LI, ResultReg);
return true;
}

bool MipsFastISel::selectStore(const Instruction *I) {
Value *Op0 = I->getOperand(0);
const StoreInst *SI = cast<StoreInst>(I);

Value *Op0 = SI->getOperand(0);
unsigned SrcReg = 0;

// Atomic stores need special handling.
if (cast<StoreInst>(I)->isAtomic())
if (SI->isAtomic())
return false;

// Verify we have a legal type before going any further.
MVT VT;
if (!isLoadTypeLegal(I->getOperand(0)->getType(), VT))
if (!isLoadTypeLegal(SI->getOperand(0)->getType(), VT))
return false;

// Underaligned stores need special handling.
if (SI->getAlign() < VT.getFixedSizeInBits() / 8 &&
!Subtarget->systemSupportsUnalignedAccess())
return false;

// Get the value to be stored into a register.
Expand All @@ -922,7 +936,7 @@ bool MipsFastISel::selectStore(const Instruction *I) {

// See if we can handle this address.
Address Addr;
if (!computeAddress(I->getOperand(1), Addr))
if (!computeAddress(SI->getOperand(1), Addr))
return false;

if (!emitStore(VT, SrcReg, Addr))
Expand Down
109 changes: 109 additions & 0 deletions llvm/test/CodeGen/Mips/Fast-ISel/underaligned-load-store.ll
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,109 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
; RUN: llc < %s -march mips -fast-isel -relocation-model pic | FileCheck %s -check-prefixes=MIPS-32
; RUN: llc < %s -march mips64 -fast-isel -relocation-model pic | FileCheck %s -check-prefixes=MIPS-64
; RUN: llc < %s -march mips -mcpu mips32r6 -fast-isel -relocation-model pic | FileCheck %s -check-prefixes=MIPS-32-R6
; RUN: llc < %s -march mips -mcpu mips32r6 -mattr +strict-align -fast-isel -relocation-model pic | FileCheck %s -check-prefixes=MIPS-32-R6-STRICT
; RUN: llc < %s -march mips64 -mcpu mips64r6 -fast-isel -relocation-model pic | FileCheck %s -check-prefixes=MIPS-64-R6
; RUN: llc < %s -march mips64 -mcpu mips64r6 -mattr +strict-align -fast-isel -relocation-model pic | FileCheck %s -check-prefixes=MIPS-64-R6-STRICT

@var = external global i32, align 1

; FastISel should bail on the underaligned load and store, except on r6 with non-strict alignment.
define dso_local ccc i32 @__start() {
; MIPS-32-LABEL: __start:
; MIPS-32: # %bb.0:
; MIPS-32-NEXT: lui $2, %hi(_gp_disp)
; MIPS-32-NEXT: addiu $2, $2, %lo(_gp_disp)
; MIPS-32-NEXT: addu $1, $2, $25
; MIPS-32-NEXT: lw $1, %got(var)($1)
; MIPS-32-NEXT: lwl $2, 0($1)
; MIPS-32-NEXT: lwr $2, 3($1)
; MIPS-32-NEXT: addiu $3, $zero, 42
; MIPS-32-NEXT: swl $3, 0($1)
; MIPS-32-NEXT: jr $ra
; MIPS-32-NEXT: swr $3, 3($1)
;
; MIPS-64-LABEL: __start:
; MIPS-64: # %bb.0:
; MIPS-64-NEXT: lui $1, %hi(%neg(%gp_rel(__start)))
; MIPS-64-NEXT: daddu $1, $1, $25
; MIPS-64-NEXT: daddiu $1, $1, %lo(%neg(%gp_rel(__start)))
; MIPS-64-NEXT: ld $1, %got_disp(var)($1)
; MIPS-64-NEXT: lwl $2, 0($1)
; MIPS-64-NEXT: lwr $2, 3($1)
; MIPS-64-NEXT: addiu $3, $zero, 42
; MIPS-64-NEXT: swl $3, 0($1)
; MIPS-64-NEXT: jr $ra
; MIPS-64-NEXT: swr $3, 3($1)
;
; MIPS-32-R6-LABEL: __start:
; MIPS-32-R6: # %bb.0:
; MIPS-32-R6-NEXT: lui $2, %hi(_gp_disp)
; MIPS-32-R6-NEXT: addiu $2, $2, %lo(_gp_disp)
; MIPS-32-R6-NEXT: addu $1, $2, $25
; MIPS-32-R6-NEXT: lw $1, %got(var)($1)
; MIPS-32-R6-NEXT: lw $2, 0($1)
; MIPS-32-R6-NEXT: addiu $3, $zero, 42
; MIPS-32-R6-NEXT: jr $ra
; MIPS-32-R6-NEXT: sw $3, 0($1)
;
; MIPS-32-R6-STRICT-LABEL: __start:
; MIPS-32-R6-STRICT: # %bb.0:
; MIPS-32-R6-STRICT-NEXT: lui $2, %hi(_gp_disp)
; MIPS-32-R6-STRICT-NEXT: addiu $2, $2, %lo(_gp_disp)
; MIPS-32-R6-STRICT-NEXT: addu $1, $2, $25
; MIPS-32-R6-STRICT-NEXT: lw $1, %got(var)($1)
; MIPS-32-R6-STRICT-NEXT: lbu $2, 0($1)
; MIPS-32-R6-STRICT-NEXT: lbu $3, 1($1)
; MIPS-32-R6-STRICT-NEXT: lbu $4, 3($1)
; MIPS-32-R6-STRICT-NEXT: lbu $5, 2($1)
; MIPS-32-R6-STRICT-NEXT: addiu $6, $zero, 42
; MIPS-32-R6-STRICT-NEXT: sb $zero, 2($1)
; MIPS-32-R6-STRICT-NEXT: sb $6, 3($1)
; MIPS-32-R6-STRICT-NEXT: sb $zero, 0($1)
; MIPS-32-R6-STRICT-NEXT: sb $zero, 1($1)
; MIPS-32-R6-STRICT-NEXT: sll $1, $5, 8
; MIPS-32-R6-STRICT-NEXT: or $1, $1, $4
; MIPS-32-R6-STRICT-NEXT: sll $3, $3, 16
; MIPS-32-R6-STRICT-NEXT: sll $2, $2, 24
; MIPS-32-R6-STRICT-NEXT: or $2, $2, $3
; MIPS-32-R6-STRICT-NEXT: jr $ra
; MIPS-32-R6-STRICT-NEXT: or $2, $2, $1
;
; MIPS-64-R6-LABEL: __start:
; MIPS-64-R6: # %bb.0:
; MIPS-64-R6-NEXT: lui $1, %hi(%neg(%gp_rel(__start)))
; MIPS-64-R6-NEXT: daddu $1, $1, $25
; MIPS-64-R6-NEXT: daddiu $1, $1, %lo(%neg(%gp_rel(__start)))
; MIPS-64-R6-NEXT: ld $1, %got_disp(var)($1)
; MIPS-64-R6-NEXT: lw $2, 0($1)
; MIPS-64-R6-NEXT: addiu $3, $zero, 42
; MIPS-64-R6-NEXT: jr $ra
; MIPS-64-R6-NEXT: sw $3, 0($1)
;
; MIPS-64-R6-STRICT-LABEL: __start:
; MIPS-64-R6-STRICT: # %bb.0:
; MIPS-64-R6-STRICT-NEXT: lui $1, %hi(%neg(%gp_rel(__start)))
; MIPS-64-R6-STRICT-NEXT: daddu $1, $1, $25
; MIPS-64-R6-STRICT-NEXT: daddiu $1, $1, %lo(%neg(%gp_rel(__start)))
; MIPS-64-R6-STRICT-NEXT: ld $1, %got_disp(var)($1)
; MIPS-64-R6-STRICT-NEXT: lbu $2, 0($1)
; MIPS-64-R6-STRICT-NEXT: lbu $3, 1($1)
; MIPS-64-R6-STRICT-NEXT: lbu $4, 3($1)
; MIPS-64-R6-STRICT-NEXT: lbu $5, 2($1)
; MIPS-64-R6-STRICT-NEXT: addiu $6, $zero, 42
; MIPS-64-R6-STRICT-NEXT: sb $zero, 2($1)
; MIPS-64-R6-STRICT-NEXT: sb $6, 3($1)
; MIPS-64-R6-STRICT-NEXT: sb $zero, 0($1)
; MIPS-64-R6-STRICT-NEXT: sb $zero, 1($1)
; MIPS-64-R6-STRICT-NEXT: sll $1, $5, 8
; MIPS-64-R6-STRICT-NEXT: or $1, $1, $4
; MIPS-64-R6-STRICT-NEXT: sll $3, $3, 16
; MIPS-64-R6-STRICT-NEXT: sll $2, $2, 24
; MIPS-64-R6-STRICT-NEXT: or $2, $2, $3
; MIPS-64-R6-STRICT-NEXT: jr $ra
; MIPS-64-R6-STRICT-NEXT: or $2, $2, $1
%1 = load i32, ptr @var, align 1
store i32 42, ptr @var, align 1
ret i32 %1
}

0 comments on commit 1299cc9

Please sign in to comment.