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| author | Sanjay Patel <spatel@rotateright.com> | 2017-06-20 12:40:55 +0000 |
|---|---|---|
| committer | Sanjay Patel <spatel@rotateright.com> | 2017-06-20 12:40:55 +0000 |
| commit | adca825dc14fcdda6425bebcb2f342ea45231ac5 (patch) | |
| tree | 575c2bb7d1b24d439d49b10b19704221dbbbf4fc /llvm/test/Transforms | |
| parent | a6e2cebf98c5538c4796fedb7354c87cb0dd2c7d (diff) | |
| download | bcm5719-llvm-adca825dc14fcdda6425bebcb2f342ea45231ac5.tar.gz bcm5719-llvm-adca825dc14fcdda6425bebcb2f342ea45231ac5.zip | |
[InstCombine] try to canonicalize xor-of-icmps to and-of-icmps
We have a large portfolio of folds for and-of-icmps and or-of-icmps in InstSimplify and InstCombine,
but hardly anything for xor-of-icmps. Rather than trying to rethink and translate all of those folds,
we can use the truth table definition of xor:
X ^ Y --> (X | Y) & !(X & Y)
...to see if we can convert the xor to and/or and then use the existing folds.
http://rise4fun.com/Alive/J9v
Differential Revision: https://reviews.llvm.org/D33342
llvm-svn: 305792
Diffstat (limited to 'llvm/test/Transforms')
| -rw-r--r-- | llvm/test/Transforms/InstCombine/set.ll | 18 |
1 files changed, 7 insertions, 11 deletions
diff --git a/llvm/test/Transforms/InstCombine/set.ll b/llvm/test/Transforms/InstCombine/set.ll index db2b4c3558e..1452015d2ef 100644 --- a/llvm/test/Transforms/InstCombine/set.ll +++ b/llvm/test/Transforms/InstCombine/set.ll @@ -164,10 +164,8 @@ define i1 @bool_eq0(i64 %a) { define i1 @xor_of_icmps(i64 %a) { ; CHECK-LABEL: @xor_of_icmps( -; CHECK-NEXT: [[B:%.*]] = icmp sgt i64 %a, 0 -; CHECK-NEXT: [[C:%.*]] = icmp eq i64 %a, 1 -; CHECK-NEXT: [[XOR:%.*]] = xor i1 [[C]], [[B]] -; CHECK-NEXT: ret i1 [[XOR]] +; CHECK-NEXT: [[TMP1:%.*]] = icmp sgt i64 %a, 1 +; CHECK-NEXT: ret i1 [[TMP1]] ; %b = icmp sgt i64 %a, 0 %c = icmp eq i64 %a, 1 @@ -179,10 +177,8 @@ define i1 @xor_of_icmps(i64 %a) { define i1 @xor_of_icmps_commute(i64 %a) { ; CHECK-LABEL: @xor_of_icmps_commute( -; CHECK-NEXT: [[B:%.*]] = icmp sgt i64 %a, 0 -; CHECK-NEXT: [[C:%.*]] = icmp eq i64 %a, 1 -; CHECK-NEXT: [[XOR:%.*]] = xor i1 [[B]], [[C]] -; CHECK-NEXT: ret i1 [[XOR]] +; CHECK-NEXT: [[TMP1:%.*]] = icmp sgt i64 %a, 1 +; CHECK-NEXT: ret i1 [[TMP1]] ; %b = icmp sgt i64 %a, 0 %c = icmp eq i64 %a, 1 @@ -209,10 +205,10 @@ define i1 @xor_of_icmps_folds_more(i64 %a) { define i32 @PR2844(i32 %x) { ; CHECK-LABEL: @PR2844( -; CHECK-NEXT: [[A:%.*]] = icmp eq i32 %x, 0 +; CHECK-NEXT: [[A:%.*]] = icmp ne i32 %x, 0 ; CHECK-NEXT: [[B:%.*]] = icmp sgt i32 %x, -638208502 -; CHECK-NEXT: [[NOT_OR:%.*]] = xor i1 [[A]], [[B]] -; CHECK-NEXT: [[SEL:%.*]] = zext i1 [[NOT_OR]] to i32 +; CHECK-NEXT: [[TMP1:%.*]] = and i1 [[A]], [[B]] +; CHECK-NEXT: [[SEL:%.*]] = zext i1 [[TMP1]] to i32 ; CHECK-NEXT: ret i32 [[SEL]] ; %A = icmp eq i32 %x, 0 |
