287294d54d
Consider the following case:
```
define i1 @pr140481(i32 %x) {
%cond = icmp slt i32 %x, 0
call void @llvm.assume(i1 %cond)
%add = add nsw i32 %x, 5001000
%mul1 = mul nsw i32 %add, -5001000
%mul2 = mul nsw i32 %mul1, 5001000
%cmp2 = icmp sgt i32 %mul2, 0
ret i1 %cmp2
}
```
Before this patch, `decompose(%mul2)` returns `-25010001000000 * %x +
4052193514966861312`.
Therefore, `%cmp2` will be simplified into true because `%x s< 0 &&
-25010001000000 * %x + 4052193514966861312 s<= 0` is unsat.
It is incorrect since the offset `-25010001000000 * 5001000 ->
4052193514966861312` signed wraps.
This patch treats a decomposition as invalid if overflows occur when
computing coefficients.
Closes https://github.com/llvm/llvm-project/issues/140481.
77 lines
2.4 KiB
LLVM
77 lines
2.4 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
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; RUN: opt -passes=constraint-elimination -S %s | FileCheck %s
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define i32 @f(i64 %a3, i64 %numElements) {
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; CHECK-LABEL: define i32 @f(
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; CHECK-SAME: i64 [[A3:%.*]], i64 [[NUMELEMENTS:%.*]]) {
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[COND:%.*]] = icmp ule i64 [[NUMELEMENTS]], 1152921504606846975
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; CHECK-NEXT: call void @llvm.assume(i1 [[COND]])
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; CHECK-NEXT: [[A1:%.*]] = shl nuw i64 [[NUMELEMENTS]], 4
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; CHECK-NEXT: br label [[IF_END:%.*]]
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; CHECK: if.end:
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; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i64 [[A1]], [[A3]]
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; CHECK-NEXT: br i1 [[CMP]], label [[IF_END_I:%.*]], label [[ABORT:%.*]]
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; CHECK: if.end.i:
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; CHECK-NEXT: [[CMP2_NOT_I:%.*]] = icmp ult i64 [[A1]], [[A3]]
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; CHECK-NEXT: br i1 [[CMP2_NOT_I]], label [[ABORT]], label [[EXIT:%.*]]
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; CHECK: abort:
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; CHECK-NEXT: ret i32 -1
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; CHECK: exit:
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; CHECK-NEXT: ret i32 0
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;
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entry:
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%cond = icmp ule i64 %numElements, 1152921504606846975
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call void @llvm.assume(i1 %cond)
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%a1 = shl nuw i64 %numElements, 4
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br label %if.end
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if.end:
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%cmp = icmp ugt i64 %a1, %a3
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br i1 %cmp, label %if.end.i, label %abort
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if.end.i:
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%cmp2.not.i = icmp ult i64 %a1, %a3
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br i1 %cmp2.not.i, label %abort, label %exit
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abort:
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ret i32 -1
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exit:
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ret i32 0
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}
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declare void @llvm.assume(i1)
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define i1 @negate_overflow_add_1(i64 %x) {
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; CHECK-LABEL: define i1 @negate_overflow_add_1(
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; CHECK-SAME: i64 [[X:%.*]]) {
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[SUB:%.*]] = add nsw i64 [[X]], -9223372036854775807
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; CHECK-NEXT: [[C:%.*]] = icmp slt i64 0, [[SUB]]
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; CHECK-NEXT: ret i1 [[C]]
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;
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entry:
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%sub = add nsw i64 %x, -9223372036854775807
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%c = icmp slt i64 0, %sub
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ret i1 %c
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}
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define i1 @pr140481(i32 %x) {
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; CHECK-LABEL: define i1 @pr140481(
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; CHECK-SAME: i32 [[X:%.*]]) {
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[COND:%.*]] = icmp slt i32 [[X]], 0
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; CHECK-NEXT: call void @llvm.assume(i1 [[COND]])
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; CHECK-NEXT: [[ADD:%.*]] = add nsw i32 [[X]], 5001000
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; CHECK-NEXT: [[MUL1:%.*]] = mul nsw i32 [[ADD]], -5001000
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; CHECK-NEXT: [[MUL2:%.*]] = mul nsw i32 [[MUL1]], 5001000
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; CHECK-NEXT: [[CMP2:%.*]] = icmp sgt i32 [[MUL2]], 0
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; CHECK-NEXT: ret i1 [[CMP2]]
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;
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entry:
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%cond = icmp slt i32 %x, 0
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call void @llvm.assume(i1 %cond)
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%add = add nsw i32 %x, 5001000
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%mul1 = mul nsw i32 %add, -5001000
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%mul2 = mul nsw i32 %mul1, 5001000
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%cmp2 = icmp sgt i32 %mul2, 0
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ret i1 %cmp2
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}
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