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https://github.com/RPCS3/llvm-mirror.git
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bf21903aff
When we have a parameter (or call site return) with a dereferenceable
attribute, it can specify the size of an array pointed to by that parameter. If
we have a value for which we can accumulate a constant offset to such a
parameter, then we can use that offset in a direct comparison with the size
specified by the dereferenceable attribute.
This enables us to handle cases like this:
int foo(int a[static 3]) {
return a[2]; /* this is always dereferenceable */
}
llvm-svn: 213447
169 lines
6.2 KiB
LLVM
169 lines
6.2 KiB
LLVM
; RUN: opt -S -basicaa -licm < %s | FileCheck %s
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target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-unknown-linux-gnu"
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; This test represents the following function:
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; void test1(int * __restrict__ a, int * __restrict__ b, int &c, int n) {
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; for (int i = 0; i < n; ++i)
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; if (a[i] > 0)
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; a[i] = c*b[i];
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; }
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; and we want to hoist the load of %c out of the loop. This can be done only
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; because the dereferenceable attribute is on %c.
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; CHECK-LABEL: @test1
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; CHECK: load i32* %c, align 4
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; CHECK: for.body:
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define void @test1(i32* noalias nocapture %a, i32* noalias nocapture readonly %b, i32* nocapture readonly nonnull dereferenceable(4) %c, i32 %n) #0 {
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entry:
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%cmp11 = icmp sgt i32 %n, 0
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br i1 %cmp11, label %for.body, label %for.end
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for.body: ; preds = %entry, %for.inc
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%indvars.iv = phi i64 [ %indvars.iv.next, %for.inc ], [ 0, %entry ]
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%arrayidx = getelementptr inbounds i32* %a, i64 %indvars.iv
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%0 = load i32* %arrayidx, align 4
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%cmp1 = icmp sgt i32 %0, 0
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br i1 %cmp1, label %if.then, label %for.inc
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if.then: ; preds = %for.body
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%1 = load i32* %c, align 4
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%arrayidx3 = getelementptr inbounds i32* %b, i64 %indvars.iv
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%2 = load i32* %arrayidx3, align 4
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%mul = mul nsw i32 %2, %1
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store i32 %mul, i32* %arrayidx, align 4
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br label %for.inc
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for.inc: ; preds = %for.body, %if.then
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%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
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%lftr.wideiv = trunc i64 %indvars.iv.next to i32
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%exitcond = icmp eq i32 %lftr.wideiv, %n
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br i1 %exitcond, label %for.end, label %for.body
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for.end: ; preds = %for.inc, %entry
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ret void
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}
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; This is the same as @test1, but without the dereferenceable attribute on %c.
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; Without this attribute, we should not hoist the load of %c.
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; CHECK-LABEL: @test2
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; CHECK: if.then:
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; CHECK: load i32* %c, align 4
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define void @test2(i32* noalias nocapture %a, i32* noalias nocapture readonly %b, i32* nocapture readonly nonnull %c, i32 %n) #0 {
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entry:
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%cmp11 = icmp sgt i32 %n, 0
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br i1 %cmp11, label %for.body, label %for.end
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for.body: ; preds = %entry, %for.inc
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%indvars.iv = phi i64 [ %indvars.iv.next, %for.inc ], [ 0, %entry ]
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%arrayidx = getelementptr inbounds i32* %a, i64 %indvars.iv
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%0 = load i32* %arrayidx, align 4
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%cmp1 = icmp sgt i32 %0, 0
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br i1 %cmp1, label %if.then, label %for.inc
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if.then: ; preds = %for.body
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%1 = load i32* %c, align 4
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%arrayidx3 = getelementptr inbounds i32* %b, i64 %indvars.iv
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%2 = load i32* %arrayidx3, align 4
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%mul = mul nsw i32 %2, %1
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store i32 %mul, i32* %arrayidx, align 4
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br label %for.inc
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for.inc: ; preds = %for.body, %if.then
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%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
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%lftr.wideiv = trunc i64 %indvars.iv.next to i32
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%exitcond = icmp eq i32 %lftr.wideiv, %n
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br i1 %exitcond, label %for.end, label %for.body
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for.end: ; preds = %for.inc, %entry
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ret void
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}
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; This test represents the following function:
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; void test3(int * restrict a, int * restrict b, int c[static 3], int n) {
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; for (int i = 0; i < n; ++i)
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; if (a[i] > 0)
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; a[i] = c[2]*b[i];
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; }
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; and we want to hoist the load of c[2] out of the loop. This can be done only
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; because the dereferenceable attribute is on %c.
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; CHECK-LABEL: @test3
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; CHECK: load i32* %c2, align 4
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; CHECK: for.body:
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define void @test3(i32* noalias nocapture %a, i32* noalias nocapture readonly %b, i32* nocapture readonly dereferenceable(12) %c, i32 %n) #0 {
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entry:
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%cmp11 = icmp sgt i32 %n, 0
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br i1 %cmp11, label %for.body, label %for.end
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for.body: ; preds = %entry, %for.inc
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%indvars.iv = phi i64 [ %indvars.iv.next, %for.inc ], [ 0, %entry ]
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%arrayidx = getelementptr inbounds i32* %a, i64 %indvars.iv
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%0 = load i32* %arrayidx, align 4
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%cmp1 = icmp sgt i32 %0, 0
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br i1 %cmp1, label %if.then, label %for.inc
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if.then: ; preds = %for.body
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%c2 = getelementptr inbounds i32* %c, i64 2
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%1 = load i32* %c2, align 4
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%arrayidx3 = getelementptr inbounds i32* %b, i64 %indvars.iv
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%2 = load i32* %arrayidx3, align 4
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%mul = mul nsw i32 %2, %1
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store i32 %mul, i32* %arrayidx, align 4
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br label %for.inc
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for.inc: ; preds = %for.body, %if.then
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%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
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%lftr.wideiv = trunc i64 %indvars.iv.next to i32
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%exitcond = icmp eq i32 %lftr.wideiv, %n
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br i1 %exitcond, label %for.end, label %for.body
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for.end: ; preds = %for.inc, %entry
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ret void
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}
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; This is the same as @test3, but with a dereferenceable attribute on %c with a
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; size too small to cover c[2] (and so we should not hoist it).
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; CHECK-LABEL: @test4
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; CHECK: if.then:
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; CHECK: load i32* %c2, align 4
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define void @test4(i32* noalias nocapture %a, i32* noalias nocapture readonly %b, i32* nocapture readonly dereferenceable(11) %c, i32 %n) #0 {
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entry:
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%cmp11 = icmp sgt i32 %n, 0
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br i1 %cmp11, label %for.body, label %for.end
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for.body: ; preds = %entry, %for.inc
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%indvars.iv = phi i64 [ %indvars.iv.next, %for.inc ], [ 0, %entry ]
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%arrayidx = getelementptr inbounds i32* %a, i64 %indvars.iv
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%0 = load i32* %arrayidx, align 4
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%cmp1 = icmp sgt i32 %0, 0
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br i1 %cmp1, label %if.then, label %for.inc
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if.then: ; preds = %for.body
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%c2 = getelementptr inbounds i32* %c, i64 2
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%1 = load i32* %c2, align 4
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%arrayidx3 = getelementptr inbounds i32* %b, i64 %indvars.iv
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%2 = load i32* %arrayidx3, align 4
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%mul = mul nsw i32 %2, %1
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store i32 %mul, i32* %arrayidx, align 4
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br label %for.inc
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for.inc: ; preds = %for.body, %if.then
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%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
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%lftr.wideiv = trunc i64 %indvars.iv.next to i32
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%exitcond = icmp eq i32 %lftr.wideiv, %n
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br i1 %exitcond, label %for.end, label %for.body
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for.end: ; preds = %for.inc, %entry
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ret void
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}
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attributes #0 = { nounwind uwtable }
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