This also required making recursive simplifications until
nothing changes or a hard limit (currently 3) is hit.
With the simplification in place indvars can canonicalize
loops of the form
for (unsigned i = 0; i < a-b; ++i)
into
for (unsigned i = 0; i != a-b; ++i)
which used to fail because SCEV created a weird umax expr
for the backedge taken count.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157701 91177308-0d34-0410-b5e6-96231b3b80d8
If integer overflow causes one of the terms to reach zero, that can
force the entire expression to zero.
Fixes PR12929: cast<Ty>() argument of incompatible type
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157673 91177308-0d34-0410-b5e6-96231b3b80d8
getUDivExpr attempts to simplify by checking for overflow.
isLoopEntryGuardedByCond then evaluates the loop predicate which
may lead to the same getUDivExpr causing endless recursion.
Fixes PR12868: clang 3.2 segmentation fault.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157092 91177308-0d34-0410-b5e6-96231b3b80d8
This allows us to keep passing reduced masks to SimplifyDemandedBits, but
know about all the bits if SimplifyDemandedBits fails. This allows instcombine
to simplify cases like the one in the included testcase.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154011 91177308-0d34-0410-b5e6-96231b3b80d8
instead of its own hard coded thing, allowing it to handle
ConstantDataSequential and fixing some obscure bugs (e.g. it would
previously crash on a CAZ of vector type).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148788 91177308-0d34-0410-b5e6-96231b3b80d8
bots. Original commit messages:
- Reapply r142781 with fix. Original message:
Enhance SCEV's brute force loop analysis to handle multiple PHI nodes in the
loop header when computing the trip count.
With this, we now constant evaluate:
struct ListNode { const struct ListNode *next; int i; };
static const struct ListNode node1 = {0, 1};
static const struct ListNode node2 = {&node1, 2};
static const struct ListNode node3 = {&node2, 3};
int test() {
int sum = 0;
for (const struct ListNode *n = &node3; n != 0; n = n->next)
sum += n->i;
return sum;
}
- Now that we look at all the header PHIs, we need to consider all the header PHIs
when deciding that the loop has stopped evolving. Fixes miscompile in the gcc
torture testsuite!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142919 91177308-0d34-0410-b5e6-96231b3b80d8
the dragonegg and llvm-gcc self-host buildbots. Original commit
messages:
- Reapply r142781 with fix. Original message:
Enhance SCEV's brute force loop analysis to handle multiple PHI nodes in the
loop header when computing the trip count.
With this, we now constant evaluate:
struct ListNode { const struct ListNode *next; int i; };
static const struct ListNode node1 = {0, 1};
static const struct ListNode node2 = {&node1, 2};
static const struct ListNode node3 = {&node2, 3};
int test() {
int sum = 0;
for (const struct ListNode *n = &node3; n != 0; n = n->next)
sum += n->i;
return sum;
}
- Now that we look at all the header PHIs, we need to consider all the header PHIs
when deciding that the loop has stopped evolving. Fixes miscompile in the gcc
torture testsuite!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142916 91177308-0d34-0410-b5e6-96231b3b80d8
state. Furthermore, they might not have two operands. This fixes the underlying
issue behind the crashes introduced in r142781.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142788 91177308-0d34-0410-b5e6-96231b3b80d8
Assertion `i_nocapture < OperandTraits<PHINode>::operands(this) && "getOperand() out of range!"' failed.
coming out of indvars.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142786 91177308-0d34-0410-b5e6-96231b3b80d8
able to constant fold load instructions where the argument is a constant.
Second, we should be able to watch multiple PHI nodes through the loop; this
patch only supports PHIs in loop headers, more can be done here.
With this patch, we now constant evaluate:
static const int arr[] = {1, 2, 3, 4, 5};
int test() {
int sum = 0;
for (int i = 0; i < 5; ++i) sum += arr[i];
return sum;
}
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142731 91177308-0d34-0410-b5e6-96231b3b80d8
could be arguments, for example.
No testcase because this is a bug-fix broken out of a larger optimization patch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141951 91177308-0d34-0410-b5e6-96231b3b80d8
I noticed during self-review that my previous checkin disabled some
analysis. Even with the reenabled analysis the test case runs in about
5ms. Without the fix, it will take several minutes at least.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141164 91177308-0d34-0410-b5e6-96231b3b80d8
Note to compiler writers: never recurse on multiple instruction
operands without memoization.
Fixes rdar://10187945. Was taking 45s, now taking 5ms.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141161 91177308-0d34-0410-b5e6-96231b3b80d8
