b276dd195a
In PR41304: https://bugs.llvm.org/show_bug.cgi?id=41304 ...we have a case where we want to fold a binop of select-shuffle (blended) values. Rather than try to match commuted variants of the pattern, we can canonicalize the shuffles and check for mask equality with commuted operands. We don't produce arbitrary shuffle masks in instcombine, but select-shuffles are a special case that the backend is required to handle because we already canonicalize vector select to this shuffle form. So there should be no codegen difference from this change. It's possible that this improves CSE in IR though. Differential Revision: https://reviews.llvm.org/D60016 llvm-svn: 357366
106 lines
3.6 KiB
LLVM
106 lines
3.6 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt < %s -S -instcombine | FileCheck %s
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@A = extern_weak global i32, align 4
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@B = extern_weak global i32, align 4
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define i32 @foo(i1 %which) {
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; CHECK-LABEL: @foo(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br i1 [[WHICH:%.*]], label [[FINAL:%.*]], label [[DELAY:%.*]]
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; CHECK: delay:
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; CHECK-NEXT: br label [[FINAL]]
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; CHECK: final:
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; CHECK-NEXT: [[USE2:%.*]] = phi i32 [ 1, [[ENTRY:%.*]] ], [ select (i1 icmp eq (i32* @A, i32* @B), i32 2, i32 1), [[DELAY]] ]
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; CHECK-NEXT: ret i32 [[USE2]]
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;
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entry:
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br i1 %which, label %final, label %delay
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delay:
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br label %final
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final:
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%use2 = phi i1 [ false, %entry ], [ icmp eq (i32* @A, i32* @B), %delay ]
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%value = select i1 %use2, i32 2, i32 1
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ret i32 %value
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}
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; test folding of select into phi for vectors.
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define <4 x i64> @vec1(i1 %which) {
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; CHECK-LABEL: @vec1(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br i1 [[WHICH:%.*]], label [[FINAL:%.*]], label [[DELAY:%.*]]
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; CHECK: delay:
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; CHECK-NEXT: br label [[FINAL]]
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; CHECK: final:
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; CHECK-NEXT: [[PHINODE:%.*]] = phi <4 x i64> [ zeroinitializer, [[ENTRY:%.*]] ], [ <i64 0, i64 0, i64 126, i64 127>, [[DELAY]] ]
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; CHECK-NEXT: ret <4 x i64> [[PHINODE]]
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;
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entry:
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br i1 %which, label %final, label %delay
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delay:
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br label %final
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final:
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%phinode = phi <4 x i1> [ <i1 true, i1 true, i1 true, i1 true>, %entry ], [ <i1 true, i1 true, i1 false, i1 false>, %delay ]
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%sel = select <4 x i1> %phinode, <4 x i64> zeroinitializer, <4 x i64> <i64 124, i64 125, i64 126, i64 127>
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ret <4 x i64> %sel
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}
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define <4 x i64> @vec2(i1 %which) {
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; CHECK-LABEL: @vec2(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br i1 [[WHICH:%.*]], label [[FINAL:%.*]], label [[DELAY:%.*]]
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; CHECK: delay:
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; CHECK-NEXT: br label [[FINAL]]
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; CHECK: final:
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; CHECK-NEXT: [[PHINODE:%.*]] = phi <4 x i64> [ <i64 124, i64 125, i64 126, i64 127>, [[ENTRY:%.*]] ], [ <i64 0, i64 125, i64 0, i64 127>, [[DELAY]] ]
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; CHECK-NEXT: ret <4 x i64> [[PHINODE]]
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;
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entry:
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br i1 %which, label %final, label %delay
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delay:
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br label %final
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final:
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%phinode = phi <4 x i1> [ <i1 false, i1 false, i1 false, i1 false>, %entry ], [ <i1 true, i1 false, i1 true, i1 false>, %delay ]
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%sel = select <4 x i1> %phinode, <4 x i64> zeroinitializer, <4 x i64> <i64 124, i64 125, i64 126, i64 127>
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ret <4 x i64> %sel
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}
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; Test PR33364
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; Insert the generated select into the same block as the incoming phi value.
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; phi has constant vectors along with a single non-constant vector as operands.
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define <2 x i8> @vec3(i1 %cond1, i1 %cond2, <2 x i1> %x, <2 x i8> %y, <2 x i8> %z) {
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; CHECK-LABEL: @vec3(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[PHITMP1:%.*]] = shufflevector <2 x i8> [[Z:%.*]], <2 x i8> [[Y:%.*]], <2 x i32> <i32 0, i32 3>
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; CHECK-NEXT: br i1 [[COND1:%.*]], label [[IF1:%.*]], label [[ELSE:%.*]]
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; CHECK: if1:
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; CHECK-NEXT: [[PHITMP2:%.*]] = shufflevector <2 x i8> [[Y]], <2 x i8> [[Z]], <2 x i32> <i32 0, i32 3>
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; CHECK-NEXT: br i1 [[COND2:%.*]], label [[IF2:%.*]], label [[ELSE]]
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; CHECK: if2:
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; CHECK-NEXT: [[PHITMP:%.*]] = select <2 x i1> [[X:%.*]], <2 x i8> [[Y]], <2 x i8> [[Z]]
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; CHECK-NEXT: br label [[ELSE]]
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; CHECK: else:
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; CHECK-NEXT: [[PHI:%.*]] = phi <2 x i8> [ [[PHITMP]], [[IF2]] ], [ [[PHITMP1]], [[ENTRY:%.*]] ], [ [[PHITMP2]], [[IF1]] ]
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; CHECK-NEXT: ret <2 x i8> [[PHI]]
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;
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entry:
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br i1 %cond1, label %if1, label %else
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if1:
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br i1 %cond2, label %if2, label %else
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if2:
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br label %else
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else:
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%phi = phi <2 x i1> [ %x, %if2 ], [ <i1 0, i1 1>, %entry ], [ <i1 1, i1 0>, %if1 ]
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%sel = select <2 x i1> %phi, <2 x i8> %y, <2 x i8> %z
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ret <2 x i8> %sel
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}
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