Late evaluation of the fast-math vectorization requirement.

This patch moves the verification of fast-math to just before vectorization is done. This way we can tell clang to append the command line options would that allow floating-point commutativity. Specifically those are enableing fast-math or specifying a loop hint. 

llvm-svn: 244489

1 files changed, 104 insertions, 0 deletions

diff --git a/llvm/test/Transforms/LoopVectorize/no_fpmath.ll b/llvm/test/Transforms/LoopVectorize/no_fpmath.ll
new file mode 100644
index 00000000000..709025f4cd8
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/no_fpmath.ll
@@ -0,0 +1,104 @@
+; RUN: opt < %s -loop-vectorize -S -pass-remarks='loop-vectorize' -pass-remarks-missed='loop-vectorize' -pass-remarks-analysis='loop-vectorize' 2>&1 | FileCheck %s
+
+; CHECK: remark: no_fpmath.c:6:11: loop not vectorized: vectorization requires changes in the order of operations, however IEEE 754 floating-point operations are not commutative
+; CHECK: remark: no_fpmath.c:6:14: loop not vectorized:
+; CHECK: remark: no_fpmath.c:17:14: vectorized loop (vectorization width: 2, interleaved count: 2)
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.10.0"
+
+; Function Attrs: nounwind readonly ssp uwtable
+define double @cond_sum(i32* nocapture readonly %v, i32 %n) #0 {
+entry:
+  %cmp.7 = icmp sgt i32 %n, 0, !dbg !3
+  br i1 %cmp.7, label %for.body.preheader, label %for.cond.cleanup, !dbg !8
+
+for.body.preheader:                               ; preds = %entry
+  br label %for.body, !dbg !9
+
+for.cond.cleanup.loopexit:                        ; preds = %for.body
+  %add.lcssa = phi double [ %add, %for.body ]
+  br label %for.cond.cleanup, !dbg !10
+
+for.cond.cleanup:                                 ; preds = %for.cond.cleanup.loopexit, %entry
+  %a.0.lcssa = phi double [ 0.000000e+00, %entry ], [ %add.lcssa, %for.cond.cleanup.loopexit ]
+  ret double %a.0.lcssa, !dbg !10
+
+for.body:                                         ; preds = %for.body.preheader, %for.body
+  %indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %for.body.preheader ]
+  %a.08 = phi double [ %add, %for.body ], [ 0.000000e+00, %for.body.preheader ]
+  %arrayidx = getelementptr inbounds i32, i32* %v, i64 %indvars.iv, !dbg !9
+  %0 = load i32, i32* %arrayidx, align 4, !dbg !9, !tbaa !11
+  %cmp1 = icmp eq i32 %0, 0, !dbg !15
+  %cond = select i1 %cmp1, double 3.400000e+00, double 1.150000e+00, !dbg !9
+  %add = fadd double %a.08, %cond, !dbg !16
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1, !dbg !8
+  %lftr.wideiv = trunc i64 %indvars.iv.next to i32, !dbg !8
+  %exitcond = icmp eq i32 %lftr.wideiv, %n, !dbg !8
+  br i1 %exitcond, label %for.cond.cleanup.loopexit, label %for.body, !dbg !8, !llvm.loop !17
+}
+
+; Function Attrs: nounwind readonly ssp uwtable
+define double @cond_sum_loop_hint(i32* nocapture readonly %v, i32 %n) #0 {
+entry:
+  %cmp.7 = icmp sgt i32 %n, 0, !dbg !19
+  br i1 %cmp.7, label %for.body.preheader, label %for.cond.cleanup, !dbg !21
+
+for.body.preheader:                               ; preds = %entry
+  br label %for.body, !dbg !22
+
+for.cond.cleanup.loopexit:                        ; preds = %for.body
+  %add.lcssa = phi double [ %add, %for.body ]
+  br label %for.cond.cleanup, !dbg !23
+
+for.cond.cleanup:                                 ; preds = %for.cond.cleanup.loopexit, %entry
+  %a.0.lcssa = phi double [ 0.000000e+00, %entry ], [ %add.lcssa, %for.cond.cleanup.loopexit ]
+  ret double %a.0.lcssa, !dbg !23
+
+for.body:                                         ; preds = %for.body.preheader, %for.body
+  %indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %for.body.preheader ]
+  %a.08 = phi double [ %add, %for.body ], [ 0.000000e+00, %for.body.preheader ]
+  %arrayidx = getelementptr inbounds i32, i32* %v, i64 %indvars.iv, !dbg !22
+  %0 = load i32, i32* %arrayidx, align 4, !dbg !22, !tbaa !11
+  %cmp1 = icmp eq i32 %0, 0, !dbg !24
+  %cond = select i1 %cmp1, double 3.400000e+00, double 1.150000e+00, !dbg !22
+  %add = fadd double %a.08, %cond, !dbg !25
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1, !dbg !21
+  %lftr.wideiv = trunc i64 %indvars.iv.next to i32, !dbg !21
+  %exitcond = icmp eq i32 %lftr.wideiv, %n, !dbg !21
+  br i1 %exitcond, label %for.cond.cleanup.loopexit, label %for.body, !dbg !21, !llvm.loop !26
+}
+
+attributes #0 = { nounwind }
+
+!llvm.module.flags = !{!0, !1}
+!llvm.ident = !{!2}
+
+!0 = !{i32 2, !"Debug Info Version", i32 3}
+!1 = !{i32 1, !"PIC Level", i32 2}
+!2 = !{!"clang version 3.7.0"}
+!3 = !DILocation(line: 5, column: 20, scope: !4)
+!4 = !DISubprogram(name: "cond_sum", scope: !5, file: !5, line: 1, type: !6, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: true, function: double (i32*, i32)* @cond_sum, variables: !7)
+!5 = !DIFile(filename: "no_fpmath.c", directory: "")
+!6 = !DISubroutineType(types: !7)
+!7 = !{}
+!8 = !DILocation(line: 5, column: 3, scope: !4)
+!9 = !DILocation(line: 6, column: 14, scope: !4)
+!10 = !DILocation(line: 9, column: 3, scope: !4)
+!11 = !{!12, !12, i64 0}
+!12 = !{!"int", !13, i64 0}
+!13 = !{!"omnipotent char", !14, i64 0}
+!14 = !{!"Simple C/C++ TBAA"}
+!15 = !DILocation(line: 6, column: 19, scope: !4)
+!16 = !DILocation(line: 6, column: 11, scope: !4)
+!17 = distinct !{!17, !18}
+!18 = !{!"llvm.loop.unroll.disable"}
+!19 = !DILocation(line: 16, column: 20, scope: !20)
+!20 = !DISubprogram(name: "cond_sum_loop_hint", scope: !5, file: !5, line: 12, type: !6, isLocal: false, isDefinition: true, scopeLine: 12, flags: DIFlagPrototyped, isOptimized: true, function: double (i32*, i32)* @cond_sum_loop_hint, variables: !7)
+!21 = !DILocation(line: 16, column: 3, scope: !20)
+!22 = !DILocation(line: 17, column: 14, scope: !20)
+!23 = !DILocation(line: 20, column: 3, scope: !20)
+!24 = !DILocation(line: 17, column: 19, scope: !20)
+!25 = !DILocation(line: 17, column: 11, scope: !20)
+!26 = distinct !{!26, !27, !18}
+!27 = !{!"llvm.loop.vectorize.enable", i1 true}