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| author | Sanjay Patel <spatel@rotateright.com> | 2019-06-20 22:55:28 +0000 |
|---|---|---|
| committer | Sanjay Patel <spatel@rotateright.com> | 2019-06-20 22:55:28 +0000 |
| commit | b342f026a466e6faf331d91fced29db5d39796aa (patch) | |
| tree | fa1cc0b1ac4e2e11a5d7f88839f4af38df4d307c /llvm/test/Transforms | |
| parent | 73986707bd57faab657c17acb6d219ed021f408a (diff) | |
| download | bcm5719-llvm-b342f026a466e6faf331d91fced29db5d39796aa.tar.gz bcm5719-llvm-b342f026a466e6faf331d91fced29db5d39796aa.zip | |
[InstSimplify] simplify power-of-2 (single bit set) sequences
As discussed in PR42314:
https://bugs.llvm.org/show_bug.cgi?id=42314
Improving the canonicalization for these patterns:
rL363956
...means we should adjust/enhance the related simplification.
https://rise4fun.com/Alive/w1cp
Name: isPow2 or zero
%x = and i32 %xx, 2048
%a = add i32 %x, -1
%r = and i32 %a, %x
=>
%r = i32 0
llvm-svn: 363997
Diffstat (limited to 'llvm/test/Transforms')
| -rw-r--r-- | llvm/test/Transforms/InstSimplify/AndOrXor.ll | 10 |
1 files changed, 2 insertions, 8 deletions
diff --git a/llvm/test/Transforms/InstSimplify/AndOrXor.ll b/llvm/test/Transforms/InstSimplify/AndOrXor.ll index e2c17e24028..a5c8108d0a5 100644 --- a/llvm/test/Transforms/InstSimplify/AndOrXor.ll +++ b/llvm/test/Transforms/InstSimplify/AndOrXor.ll @@ -93,10 +93,7 @@ define i64 @pow2b(i32 %x) { define i32 @pow2_decrement(i32 %p) { ; CHECK-LABEL: @pow2_decrement( -; CHECK-NEXT: [[X:%.*]] = shl i32 1, [[P:%.*]] -; CHECK-NEXT: [[A:%.*]] = add i32 [[X]], -1 -; CHECK-NEXT: [[R:%.*]] = and i32 [[A]], [[X]] -; CHECK-NEXT: ret i32 [[R]] +; CHECK-NEXT: ret i32 0 ; %x = shl i32 1, %p %a = add i32 %x, -1 @@ -106,10 +103,7 @@ define i32 @pow2_decrement(i32 %p) { define <2 x i32> @pow2_decrement_commute_vec(<2 x i32> %p) { ; CHECK-LABEL: @pow2_decrement_commute_vec( -; CHECK-NEXT: [[X:%.*]] = and <2 x i32> [[P:%.*]], <i32 2048, i32 2048> -; CHECK-NEXT: [[A:%.*]] = add <2 x i32> [[X]], <i32 -1, i32 -1> -; CHECK-NEXT: [[R:%.*]] = and <2 x i32> [[X]], [[A]] -; CHECK-NEXT: ret <2 x i32> [[R]] +; CHECK-NEXT: ret <2 x i32> zeroinitializer ; %x = and <2 x i32> %p, <i32 2048, i32 2048> %a = add <2 x i32> %x, <i32 -1, i32 -1> |
