diff options
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp | 22 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/vec_sext.ll | 28 |
2 files changed, 5 insertions, 45 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp index 3cf38c33853..6d0e8821e8f 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp @@ -976,28 +976,16 @@ Instruction *InstCombiner::transformSExtICmp(ICmpInst *ICI, Instruction &CI) { // (x <s 0) ? -1 : 0 -> ashr x, 31 -> all ones if negative // (x >s -1) ? -1 : 0 -> not (ashr x, 31) -> all ones if positive if ((Pred == ICmpInst::ICMP_SLT && Op1C->isNullValue()) || - (Pred == ICmpInst::ICMP_SGT && Op1C->isAllOnesValue()) || + (Pred == ICmpInst::ICMP_SGT && Op1C->isAllOnesValue())) { - // The following patterns should only be present for vectors. - // For scalar integers, the comparison should be canonicalized to one of - // the above forms. We don't do that for vectors because vector ISAs may - // not have a full range of comparison operators. This transform, - // however, will simplify the IR, so we always do it. - // - // (x <=s -1) ? -1 : 0 -> ashr x, 31 -> all ones if negative - // (x >=s 0) ? -1 : 0 -> not (ashr x, 31) -> all ones if positive - (Pred == ICmpInst::ICMP_SLE && Op1C->isAllOnesValue()) || - (Pred == ICmpInst::ICMP_SGE && Op1C->isNullValue())) { Value *Sh = ConstantInt::get(Op0->getType(), - Op0->getType()->getScalarSizeInBits() - 1); - Value *In = Builder->CreateAShr(Op0, Sh, Op0->getName() + ".lobit"); + Op0->getType()->getScalarSizeInBits()-1); + Value *In = Builder->CreateAShr(Op0, Sh, Op0->getName()+".lobit"); if (In->getType() != CI.getType()) In = Builder->CreateIntCast(In, CI.getType(), true/*SExt*/); - // Invert the sign bit if the comparison was checking for 'is positive'. - if (Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SGE) - In = Builder->CreateNot(In, In->getName() + ".not"); - + if (Pred == ICmpInst::ICMP_SGT) + In = Builder->CreateNot(In, In->getName()+".not"); return replaceInstUsesWith(CI, In); } } diff --git a/llvm/test/Transforms/InstCombine/vec_sext.ll b/llvm/test/Transforms/InstCombine/vec_sext.ll index 670789af050..6f0d21476e3 100644 --- a/llvm/test/Transforms/InstCombine/vec_sext.ll +++ b/llvm/test/Transforms/InstCombine/vec_sext.ll @@ -43,31 +43,3 @@ entry: ; CHECK: and <4 x i32> %b.lobit.not, %sub ; CHECK: or <4 x i32> %0, %1 } - -;;; PR26701: https://llvm.org/bugs/show_bug.cgi?id=26701 - -; Signed-less-than-or-equal to -1 is the same operation as above: smear the sign bit. - -define <2 x i32> @is_negative(<2 x i32> %a) { - %cmp = icmp sle <2 x i32> %a, <i32 -1, i32 -1> - %sext = sext <2 x i1> %cmp to <2 x i32> - ret <2 x i32> %sext - -; CHECK-LABEL: @is_negative( -; CHECK-NEXT: ashr <2 x i32> %a, <i32 31, i32 31> -; CHECK-NEXT: ret <2 x i32> -} - -; Signed-greater-than-or-equal to 0 is 'not' of the same operation as above. - -define <2 x i32> @is_positive(<2 x i32> %a) { - %cmp = icmp sge <2 x i32> %a, zeroinitializer - %sext = sext <2 x i1> %cmp to <2 x i32> - ret <2 x i32> %sext - -; CHECK-LABEL: @is_positive( -; CHECK-NEXT: [[SHIFT:%[a-zA-Z0-9.]+]] = ashr <2 x i32> %a, <i32 31, i32 31> -; CHECK-NEXT: xor <2 x i32> [[SHIFT]], <i32 -1, i32 -1> -; CHECK-NEXT: ret <2 x i32> -} - |
