[llvm] r217977 - [FastISel][AArch64] Fold mul into the address computation of memory operations.
Juergen Ributzka
juergen at apple.com
Wed Sep 17 12:19:32 PDT 2014
Author: ributzka
Date: Wed Sep 17 14:19:31 2014
New Revision: 217977
URL: http://llvm.org/viewvc/llvm-project?rev=217977&view=rev
Log:
[FastISel][AArch64] Fold mul into the address computation of memory operations.
Teach 'computeAddress' to also fold multiplies into the address computation
(when possible).
This fixes rdar://problem/18369443.
Modified:
llvm/trunk/lib/Target/AArch64/AArch64FastISel.cpp
llvm/trunk/test/CodeGen/AArch64/fast-isel-addressing-modes.ll
Modified: llvm/trunk/lib/Target/AArch64/AArch64FastISel.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64FastISel.cpp?rev=217977&r1=217976&r2=217977&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64FastISel.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64FastISel.cpp Wed Sep 17 14:19:31 2014
@@ -425,6 +425,19 @@ unsigned AArch64FastISel::fastMaterializ
return fastEmitInst_r(Opc, TLI.getRegClassFor(VT), ZReg, /*IsKill=*/true);
}
+/// \brief Check if the multiply is by a power-of-2 constant.
+static bool isMulPowOf2(const Value *I) {
+ if (const auto *MI = dyn_cast<MulOperator>(I)) {
+ if (const auto *C = dyn_cast<ConstantInt>(MI->getOperand(0)))
+ if (C->getValue().isPowerOf2())
+ return true;
+ if (const auto *C = dyn_cast<ConstantInt>(MI->getOperand(1)))
+ if (C->getValue().isPowerOf2())
+ return true;
+ }
+ return false;
+}
+
// Computes the address to get to an object.
bool AArch64FastISel::computeAddress(const Value *Obj, Address &Addr, Type *Ty)
{
@@ -589,7 +602,64 @@ bool AArch64FastISel::computeAddress(con
return true;
}
break;
+ case Instruction::Mul: {
+ if (Addr.getOffsetReg())
+ break;
+
+ if (!isMulPowOf2(U))
+ break;
+
+ const Value *LHS = U->getOperand(0);
+ const Value *RHS = U->getOperand(1);
+
+ // Canonicalize power-of-2 value to the RHS.
+ if (const auto *C = dyn_cast<ConstantInt>(LHS))
+ if (C->getValue().isPowerOf2())
+ std::swap(LHS, RHS);
+
+ assert(isa<ConstantInt>(RHS) && "Expected an ConstantInt.");
+ const auto *C = cast<ConstantInt>(RHS);
+ unsigned Val = C->getValue().logBase2();
+ if (Val < 1 || Val > 3)
+ break;
+
+ uint64_t NumBytes = 0;
+ if (Ty && Ty->isSized()) {
+ uint64_t NumBits = DL.getTypeSizeInBits(Ty);
+ NumBytes = NumBits / 8;
+ if (!isPowerOf2_64(NumBits))
+ NumBytes = 0;
+ }
+
+ if (NumBytes != (1ULL << Val))
+ break;
+
+ Addr.setShift(Val);
+ Addr.setExtendType(AArch64_AM::LSL);
+
+ if (const auto *I = dyn_cast<Instruction>(LHS))
+ if (FuncInfo.MBBMap[I->getParent()] == FuncInfo.MBB)
+ U = I;
+
+ if (const auto *ZE = dyn_cast<ZExtInst>(U))
+ if (ZE->getOperand(0)->getType()->isIntegerTy(32)) {
+ Addr.setExtendType(AArch64_AM::UXTW);
+ LHS = U->getOperand(0);
+ }
+
+ if (const auto *SE = dyn_cast<SExtInst>(U))
+ if (SE->getOperand(0)->getType()->isIntegerTy(32)) {
+ Addr.setExtendType(AArch64_AM::SXTW);
+ LHS = U->getOperand(0);
+ }
+
+ unsigned Reg = getRegForValue(LHS);
+ if (!Reg)
+ return false;
+ Addr.setOffsetReg(Reg);
+ return true;
}
+ } // end switch
if (Addr.getReg()) {
if (!Addr.getOffsetReg()) {
Modified: llvm/trunk/test/CodeGen/AArch64/fast-isel-addressing-modes.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/fast-isel-addressing-modes.ll?rev=217977&r1=217976&r2=217977&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/fast-isel-addressing-modes.ll (original)
+++ llvm/trunk/test/CodeGen/AArch64/fast-isel-addressing-modes.ll Wed Sep 17 14:19:31 2014
@@ -339,6 +339,16 @@ define i32 @load_shift_offreg_1(i64 %a)
ret i32 %3
}
+define i32 @load_mul_offreg_1(i64 %a) {
+; CHECK-LABEL: load_mul_offreg_1
+; CHECK: lsl [[REG:x[0-9]+]], x0, #2
+; CHECK: ldr {{w[0-9]+}}, {{\[}}[[REG]]{{\]}}
+ %1 = mul i64 %a, 4
+ %2 = inttoptr i64 %1 to i32*
+ %3 = load i32* %2
+ ret i32 %3
+}
+
; Load Base Register + Scaled Register Offset
define i32 @load_breg_shift_offreg_1(i64 %a, i64 %b) {
; CHECK-LABEL: load_breg_shift_offreg_1
@@ -405,6 +415,15 @@ define i32 @load_breg_shift_offreg_5(i64
ret i32 %5
}
+define i32 @load_breg_mul_offreg_1(i64 %a, i64 %b) {
+; CHECK-LABEL: load_breg_mul_offreg_1
+; CHECK: ldr {{w[0-9]+}}, [x1, x0, lsl #2]
+ %1 = mul i64 %a, 4
+ %2 = add i64 %1, %b
+ %3 = inttoptr i64 %2 to i32*
+ %4 = load i32* %3
+ ret i32 %4
+}
; Load Base Register + Scaled Register Offset + Sign/Zero extension
define i32 @load_breg_zext_shift_offreg_1(i32 %a, i64 %b) {
@@ -429,6 +448,17 @@ define i32 @load_breg_zext_shift_offreg_
ret i32 %5
}
+define i32 @load_breg_zext_mul_offreg_1(i32 %a, i64 %b) {
+; CHECK-LABEL: load_breg_zext_mul_offreg_1
+; CHECK: ldr {{w[0-9]+}}, [x1, w0, uxtw #2]
+ %1 = zext i32 %a to i64
+ %2 = mul i64 %1, 4
+ %3 = add i64 %2, %b
+ %4 = inttoptr i64 %3 to i32*
+ %5 = load i32* %4
+ ret i32 %5
+}
+
define i32 @load_breg_sext_shift_offreg_1(i32 %a, i64 %b) {
; CHECK-LABEL: load_breg_sext_shift_offreg_1
; CHECK: ldr {{w[0-9]+}}, [x1, w0, sxtw #2]
@@ -449,6 +479,17 @@ define i32 @load_breg_sext_shift_offreg_
%4 = inttoptr i64 %3 to i32*
%5 = load i32* %4
ret i32 %5
+}
+
+define i32 @load_breg_sext_mul_offreg_1(i32 %a, i64 %b) {
+; CHECK-LABEL: load_breg_sext_mul_offreg_1
+; CHECK: ldr {{w[0-9]+}}, [x1, w0, sxtw #2]
+ %1 = sext i32 %a to i64
+ %2 = mul i64 %1, 4
+ %3 = add i64 %2, %b
+ %4 = inttoptr i64 %3 to i32*
+ %5 = load i32* %4
+ ret i32 %5
}
; Load Scaled Register Offset + Immediate Offset + Sign/Zero extension
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