1; Test shrink wrapping placement is correct with respect to calls to llvm.{stacksave,stackrestore} 2 3; void f(int n, int x[]) { 4; if (n < 0) 5; return; 6; 7; int a[n]; 8; 9; for (int i = 0; i < n; i++) 10; a[i] = x[n - i - 1]; 11; 12; for (int i = 0; i < n; i++) 13; x[i] = a[i] + 1; 14; } 15; 16; RUN: llc -mtriple x86_64-linux %s -o - | FileCheck %s --check-prefix=CHECK 17 18define dso_local void @f(i32 %n, i32* nocapture %x) { 19entry: 20 %cmp = icmp slt i32 %n, 0 21 br i1 %cmp, label %return, label %if.end 22 23if.end: ; preds = %entry 24 %0 = zext i32 %n to i64 25 %1 = tail call i8* @llvm.stacksave() 26 %vla = alloca i32, i64 %0, align 16 27 %cmp132 = icmp eq i32 %n, 0 28 br i1 %cmp132, label %for.cond.cleanup8, label %for.body.lr.ph 29 30for.body.lr.ph: ; preds = %if.end 31 %sub = add i32 %n, -1 32 br label %for.body 33 34for.cond6.preheader: ; preds = %for.body 35 %cmp730 = icmp sgt i32 %n, 0 36 br i1 %cmp730, label %for.body9, label %for.cond.cleanup8 37 38for.body: ; preds = %for.body, %for.body.lr.ph 39 %indvars.iv34 = phi i64 [ 0, %for.body.lr.ph ], [ %indvars.iv.next35, %for.body ] 40 %2 = trunc i64 %indvars.iv34 to i32 41 %sub2 = sub i32 %sub, %2 42 %idxprom = sext i32 %sub2 to i64 43 %arrayidx = getelementptr inbounds i32, i32* %x, i64 %idxprom 44 %3 = load i32, i32* %arrayidx, align 4 45 %arrayidx4 = getelementptr inbounds i32, i32* %vla, i64 %indvars.iv34 46 store i32 %3, i32* %arrayidx4, align 4 47 %indvars.iv.next35 = add nuw nsw i64 %indvars.iv34, 1 48 %exitcond37 = icmp eq i64 %indvars.iv.next35, %0 49 br i1 %exitcond37, label %for.cond6.preheader, label %for.body 50 51for.cond.cleanup8: ; preds = %for.body9, %if.end, %for.cond6.preheader 52 tail call void @llvm.stackrestore(i8* %1) 53 br label %return 54 55for.body9: ; preds = %for.cond6.preheader, %for.body9 56 %indvars.iv = phi i64 [ %indvars.iv.next, %for.body9 ], [ 0, %for.cond6.preheader ] 57 %arrayidx11 = getelementptr inbounds i32, i32* %vla, i64 %indvars.iv 58 %4 = load i32, i32* %arrayidx11, align 4 59 %add = add nsw i32 %4, 1 60 %arrayidx13 = getelementptr inbounds i32, i32* %x, i64 %indvars.iv 61 store i32 %add, i32* %arrayidx13, align 4 62 %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1 63 %exitcond = icmp eq i64 %indvars.iv.next, %0 64 br i1 %exitcond, label %for.cond.cleanup8, label %for.body9 65 66return: ; preds = %entry, %for.cond.cleanup8 67 ret void 68} 69 70; Function Attrs: nounwind 71declare i8* @llvm.stacksave() 72 73; Function Attrs: nounwind 74declare void @llvm.stackrestore(i8*) 75 76; Check that llvm.stackrestore() happens before CSRs are popped off the stack 77 78; CHECK-LABEL: f 79 80; CHECK: pushq %rbp 81; CHECK: movq %rsp, %rbp 82 83; Saving the SP via llvm.stacksave() 84; CHECK: movq %rsp, [[SAVE:%r[a-z0-9]+]] 85; VLA allocation 86; CHECK: movq %rsp, [[TMP:%r[a-z0-9]+]] 87; CHECK: subq %r{{[a-z0-9]+}}, [[TMP]] 88; CHECK: movq [[TMP]], %rsp 89 90; The next instruction comes from llvm.stackrestore() 91; CHECK: movq [[SAVE]], %rsp 92; Epilogue 93; CHECK-NEXT: movq %rbp, %rsp 94; CHECK-NEXT: popq %rbp 95