1 ; RUN: opt -S -instcombine < %s | FileCheck %s 2 target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128-n8:16:32" 3 target triple = "i386-apple-darwin10.0.0" 4 5 define void @fu1(i32 %parm) nounwind ssp { 6 %1 = alloca i32, align 4 7 %ptr = alloca double*, align 4 8 store i32 %parm, i32* %1, align 4 9 store double* null, double** %ptr, align 4 10 %2 = load i32* %1, align 4 11 %3 = icmp ne i32 %2, 0 12 br i1 %3, label %4, label %10 13 14 ; <label>:4 ; preds = %0 15 %5 = load i32* %1, align 4 16 %6 = mul nsw i32 %5, 8 17 ; With "nsw", the alloca and its bitcast can be fused: 18 %7 = add nsw i32 %6, 2048 19 ; CHECK: alloca double* 20 %8 = alloca i8, i32 %7 21 %9 = bitcast i8* %8 to double* 22 store double* %9, double** %ptr, align 4 23 br label %10 24 25 ; <label>:10 ; preds = %4, %0 26 %11 = load double** %ptr, align 4 27 call void @bar(double* %11) 28 ; CHECK: ret 29 ret void 30 } 31 32 declare void @bar(double*) 33 34 define void @fu2(i32 %parm) nounwind ssp { 35 %1 = alloca i32, align 4 36 %ptr = alloca double*, align 4 37 store i32 %parm, i32* %1, align 4 38 store double* null, double** %ptr, align 4 39 %2 = load i32* %1, align 4 40 %3 = icmp ne i32 %2, 0 41 br i1 %3, label %4, label %10 42 43 ; <label>:4 ; preds = %0 44 %5 = load i32* %1, align 4 45 %6 = mul nsw i32 %5, 8 46 ; Without "nsw", the alloca and its bitcast cannot be fused: 47 %7 = add i32 %6, 2048 48 ; CHECK: alloca i8 49 %8 = alloca i8, i32 %7 50 ; CHECK-NEXT: bitcast i8* 51 %9 = bitcast i8* %8 to double* 52 store double* %9, double** %ptr, align 4 53 br label %10 54 55 ; <label>:10 ; preds = %4, %0 56 %11 = load double** %ptr, align 4 57 call void @bar(double* %11) 58 ret void 59 } 60 61
