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llvm-6502/test/Transforms/LICM/speculate.ll

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Move Instruction::isSafeToSpeculativelyExecute out of VMCore and into Analysis as a standalone function, since there's no need for it to be in VMCore. Also, update it to use isKnownNonZero and other goodies available in Analysis, making it more precise, enabling more aggressive optimization. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146610 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-14 23:49:11 +00:00
; RUN: opt -S -licm < %s | FileCheck %s
; UDiv is safe to speculate if the denominator is known non-zero.
; CHECK: @safe_udiv
; CHECK: %div = udiv i64 %x, %or
; CHECK-NEXT: br label %for.body
define void @safe_udiv(i64 %x, i64 %m, i64 %n, i32* %p, i64* %q) nounwind {
entry:
%or = or i64 %m, 1
br label %for.body
for.body: ; preds = %entry, %for.inc
%i.02 = phi i64 [ %inc, %for.inc ], [ 0, %entry ]
%arrayidx = getelementptr inbounds i32* %p, i64 %i.02
%0 = load i32* %arrayidx, align 4
%tobool = icmp eq i32 %0, 0
br i1 %tobool, label %for.inc, label %if.then
if.then: ; preds = %for.body
%div = udiv i64 %x, %or
%arrayidx1 = getelementptr inbounds i64* %q, i64 %i.02
store i64 %div, i64* %arrayidx1, align 8
br label %for.inc
for.inc: ; preds = %if.then, %for.body
%inc = add i64 %i.02, 1
%cmp = icmp slt i64 %inc, %n
br i1 %cmp, label %for.body, label %for.end
for.end: ; preds = %for.inc, %entry
ret void
}
; UDiv is unsafe to speculate if the denominator is not known non-zero.
; CHECK: @unsafe_udiv
; CHECK-NOT: udiv
; CHECK: for.body:
define void @unsafe_udiv(i64 %x, i64 %m, i64 %n, i32* %p, i64* %q) nounwind {
entry:
br label %for.body
for.body: ; preds = %entry, %for.inc
%i.02 = phi i64 [ %inc, %for.inc ], [ 0, %entry ]
%arrayidx = getelementptr inbounds i32* %p, i64 %i.02
%0 = load i32* %arrayidx, align 4
%tobool = icmp eq i32 %0, 0
br i1 %tobool, label %for.inc, label %if.then
if.then: ; preds = %for.body
%div = udiv i64 %x, %m
%arrayidx1 = getelementptr inbounds i64* %q, i64 %i.02
store i64 %div, i64* %arrayidx1, align 8
br label %for.inc
for.inc: ; preds = %if.then, %for.body
%inc = add i64 %i.02, 1
%cmp = icmp slt i64 %inc, %n
br i1 %cmp, label %for.body, label %for.end
for.end: ; preds = %for.inc, %entry
ret void
}
; SDiv is safe to speculate if the denominator is known non-zero and
; known to have at least one zero bit.
; CHECK: @safe_sdiv
; CHECK: %div = sdiv i64 %x, %or
; CHECK-NEXT: br label %for.body
define void @safe_sdiv(i64 %x, i64 %m, i64 %n, i32* %p, i64* %q) nounwind {
entry:
%and = and i64 %m, -3
%or = or i64 %and, 1
br label %for.body
for.body: ; preds = %entry, %for.inc
%i.02 = phi i64 [ %inc, %for.inc ], [ 0, %entry ]
%arrayidx = getelementptr inbounds i32* %p, i64 %i.02
%0 = load i32* %arrayidx, align 4
%tobool = icmp eq i32 %0, 0
br i1 %tobool, label %for.inc, label %if.then
if.then: ; preds = %for.body
%div = sdiv i64 %x, %or
%arrayidx1 = getelementptr inbounds i64* %q, i64 %i.02
store i64 %div, i64* %arrayidx1, align 8
br label %for.inc
for.inc: ; preds = %if.then, %for.body
%inc = add i64 %i.02, 1
%cmp = icmp slt i64 %inc, %n
br i1 %cmp, label %for.body, label %for.end
for.end: ; preds = %for.inc, %entry
ret void
}
; SDiv is unsafe to speculate if the denominator is not known non-zero.
; CHECK: @unsafe_sdiv_a
; CHECK-NOT: sdiv
; CHECK: for.body:
define void @unsafe_sdiv_a(i64 %x, i64 %m, i64 %n, i32* %p, i64* %q) nounwind {
entry:
%or = or i64 %m, 1
br label %for.body
for.body: ; preds = %entry, %for.inc
%i.02 = phi i64 [ %inc, %for.inc ], [ 0, %entry ]
%arrayidx = getelementptr inbounds i32* %p, i64 %i.02
%0 = load i32* %arrayidx, align 4
%tobool = icmp eq i32 %0, 0
br i1 %tobool, label %for.inc, label %if.then
if.then: ; preds = %for.body
%div = sdiv i64 %x, %or
%arrayidx1 = getelementptr inbounds i64* %q, i64 %i.02
store i64 %div, i64* %arrayidx1, align 8
br label %for.inc
for.inc: ; preds = %if.then, %for.body
%inc = add i64 %i.02, 1
%cmp = icmp slt i64 %inc, %n
br i1 %cmp, label %for.body, label %for.end
for.end: ; preds = %for.inc, %entry
ret void
}
; SDiv is unsafe to speculate if the denominator is not known to have a zero bit.
; CHECK: @unsafe_sdiv_b
; CHECK-NOT: sdiv
; CHECK: for.body:
define void @unsafe_sdiv_b(i64 %x, i64 %m, i64 %n, i32* %p, i64* %q) nounwind {
entry:
%and = and i64 %m, -3
br label %for.body
for.body: ; preds = %entry, %for.inc
%i.02 = phi i64 [ %inc, %for.inc ], [ 0, %entry ]
%arrayidx = getelementptr inbounds i32* %p, i64 %i.02
%0 = load i32* %arrayidx, align 4
%tobool = icmp eq i32 %0, 0
br i1 %tobool, label %for.inc, label %if.then
if.then: ; preds = %for.body
%div = sdiv i64 %x, %and
%arrayidx1 = getelementptr inbounds i64* %q, i64 %i.02
store i64 %div, i64* %arrayidx1, align 8
br label %for.inc
for.inc: ; preds = %if.then, %for.body
%inc = add i64 %i.02, 1
%cmp = icmp slt i64 %inc, %n
br i1 %cmp, label %for.body, label %for.end
for.end: ; preds = %for.inc, %entry
ret void
}
An instruction in a loop is not guaranteed to be executed just because the loop has no exit blocks. Fixes PR12706! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155884 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-01 04:03:01 +00:00
; SDiv is unsafe to speculate inside an infinite loop.
define void @unsafe_sdiv_c(i64 %a, i64 %b, i64* %p) {
entry:
; CHECK: entry:
; CHECK-NOT: sdiv
; CHECK: br label %for.body
br label %for.body
for.body:
%c = icmp eq i64 %b, 0
br i1 %c, label %backedge, label %if.then
if.then:
%d = sdiv i64 %a, %b
store i64 %d, i64* %p
br label %backedge
backedge:
br label %for.body
}
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