From adca825dc14fcdda6425bebcb2f342ea45231ac5 Mon Sep 17 00:00:00 2001 From: Sanjay Patel Date: Tue, 20 Jun 2017 12:40:55 +0000 Subject: [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 --- llvm/test/Transforms/InstCombine/set.ll | 18 +++++++----------- 1 file changed, 7 insertions(+), 11 deletions(-) (limited to 'llvm/test/Transforms/InstCombine/set.ll') 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 -- cgit v1.2.3