mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-22 10:29:35 +00:00
Divides and remainder operations do not behave like other operations when they are given poison: they turn into undefined behavior. It's really hard to know if the operands going into a div are or are not poison. Because of this, we should only choose to speculate if there are constant operands which we can easily reason about. This fixes PR21412. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221318 91177308-0d34-0410-b5e6-96231b3b80d8
188 lines
5.7 KiB
LLVM
188 lines
5.7 KiB
LLVM
; RUN: opt -S -licm < %s | FileCheck %s
|
|
|
|
; UDiv is safe to speculate if the denominator is known non-zero.
|
|
|
|
; CHECK-LABEL: @safe_udiv(
|
|
; CHECK: %div = udiv i64 %x, 2
|
|
; CHECK-NEXT: br label %for.body
|
|
|
|
define void @safe_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, 2
|
|
%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-LABEL: @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-LABEL: @safe_sdiv(
|
|
; CHECK: %div = sdiv i64 %x, 2
|
|
; 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
|
|
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, 2
|
|
%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-LABEL: @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-LABEL: @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
|
|
}
|
|
|
|
; 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
|
|
}
|