Index: llvm/trunk/lib/Target/ARM/ARM.td =================================================================== --- llvm/trunk/lib/Target/ARM/ARM.td +++ llvm/trunk/lib/Target/ARM/ARM.td @@ -330,6 +330,10 @@ "DisablePostRAScheduler", "true", "Don't schedule again after register allocation">; +// Enable use of alias analysis during code generation +def FeatureUseAA : SubtargetFeature<"use-aa", "UseAA", "true", + "Use alias analysis during codegen">; + //===----------------------------------------------------------------------===// // ARM architecture class // @@ -1006,7 +1010,8 @@ def : ProcessorModel<"cortex-r52", CortexR52Model, [ARMv8r, ProcR52, FeatureUseMISched, - FeatureFPAO]>; + FeatureFPAO, + FeatureUseAA]>; //===----------------------------------------------------------------------===// // Register File Description Index: llvm/trunk/lib/Target/ARM/ARMSubtarget.h =================================================================== --- llvm/trunk/lib/Target/ARM/ARMSubtarget.h +++ llvm/trunk/lib/Target/ARM/ARMSubtarget.h @@ -198,6 +198,9 @@ /// register allocation. bool DisablePostRAScheduler = false; + /// UseAA - True if using AA during codegen (DAGCombine, MISched, etc) + bool UseAA = false; + /// HasThumb2 - True if Thumb2 instructions are supported. bool HasThumb2 = false; @@ -723,6 +726,10 @@ /// True for some subtargets at > -O0. bool enablePostRAScheduler() const override; + /// Enable use of alias analysis during code generation (during MI + /// scheduling, DAGCombine, etc.). + bool useAA() const override { return UseAA; } + // enableAtomicExpand- True if we need to expand our atomics. bool enableAtomicExpand() const override; Index: llvm/trunk/test/CodeGen/ARM/useaa.ll =================================================================== --- llvm/trunk/test/CodeGen/ARM/useaa.ll +++ llvm/trunk/test/CodeGen/ARM/useaa.ll @@ -0,0 +1,26 @@ +; RUN: llc < %s -mtriple=armv8r-eabi -mcpu=cortex-r52 | FileCheck %s --check-prefix=CHECK --check-prefix=USEAA +; RUN: llc < %s -mtriple=armv8r-eabi -mcpu=generic | FileCheck %s --check-prefix=CHECK --check-prefix=GENERIC + +; Check we use AA during codegen, so can interleave these loads/stores. + +; CHECK-LABEL: test +; GENERIC: ldr +; GENERIC: str +; GENERIC: ldr +; GENERIC: str +; USEAA: ldr +; USEAA: ldr +; USEAA: str +; USEAA: str + +define void @test(i32* nocapture %a, i32* noalias nocapture %b) { +entry: + %0 = load i32, i32* %a, align 4 + %add = add nsw i32 %0, 10 + store i32 %add, i32* %a, align 4 + %1 = load i32, i32* %b, align 4 + %add2 = add nsw i32 %1, 20 + store i32 %add2, i32* %b, align 4 + ret void +} +