[polly] r308187 - [PPCGCodeGeneration] Generate invariant loads before trying to generate IR.

[Siddharth Bhat via llvm-commits]

Author: bollu
Date: Mon Jul 17 08:57:01 2017
New Revision: 308187

URL: http://llvm.org/viewvc/llvm-project?rev=308187&view=rev
Log:
 [PPCGCodeGeneration] Generate invariant loads before trying to generate IR.

 - We should call `preloadInvariantLoads` to make sure that code is
   generated for invariant loads in the kernel.

Differential Revision: https://reviews.llvm.org/D35410

Added:
    polly/trunk/test/GPGPU/invariant-load-array-access.ll
Modified:
    polly/trunk/lib/CodeGen/PPCGCodeGeneration.cpp

Modified: polly/trunk/lib/CodeGen/PPCGCodeGeneration.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/CodeGen/PPCGCodeGeneration.cpp?rev=308187&r1=308186&r2=308187&view=diff
==============================================================================
--- polly/trunk/lib/CodeGen/PPCGCodeGeneration.cpp (original)
+++ polly/trunk/lib/CodeGen/PPCGCodeGeneration.cpp Mon Jul 17 08:57:01 2017
@@ -2963,6 +2963,7 @@ public:
     Builder.SetInsertPoint(&*StartBlock->begin());
 
     NodeBuilder.initializeAfterRTH();
+    NodeBuilder.preloadInvariantLoads();
     NodeBuilder.create(Root);
     NodeBuilder.finalize();
 

Added: polly/trunk/test/GPGPU/invariant-load-array-access.ll
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/test/GPGPU/invariant-load-array-access.ll?rev=308187&view=auto
==============================================================================
--- polly/trunk/test/GPGPU/invariant-load-array-access.ll (added)
+++ polly/trunk/test/GPGPU/invariant-load-array-access.ll Mon Jul 17 08:57:01 2017
@@ -0,0 +1,71 @@
+; RUN: opt %loadPolly -analyze -polly-scops \
+; RUN: -polly-invariant-load-hoisting < %s| FileCheck %s -check-prefix=SCOP
+
+; RUN: opt %loadPolly -S -polly-codegen-ppcg \
+; RUN: -polly-invariant-load-hoisting < %s | FileCheck %s -check-prefix=HOST-IR
+
+
+; REQUIRES: pollyacc
+
+; Check that we detect a scop.
+; SCOP:      Function: f
+; SCOP-NEXT: Region: %for.body---%for.end
+; SCOP-NEXT: Max Loop Depth:  1
+; SCOP-NEXT: Invariant Accesses: {
+; SCOP-NEXT:         ReadAccess :=	[Reduction Type: NONE] [Scalar: 0]
+; SCOP-NEXT:             [tmp] -> { Stmt_for_body[i0] -> MemRef_control[0] };
+; SCOP-NEXT:         Execution Context: [tmp] -> {  :  }
+; SCOP-NEXT:         ReadAccess :=	[Reduction Type: NONE] [Scalar: 0]
+; SCOP-NEXT:             [tmp] -> { Stmt_if_then[i0] -> MemRef_readarr[0] };
+; SCOP-NEXT:         Execution Context: [tmp] -> {  : tmp >= 4 }
+; SCOP-NEXT: }
+
+; Check that kernel launch is generated in host IR.
+; the declare would not be generated unless a call to a kernel exists.
+; HOST-IR: declare void @polly_launchKernel(i8*, i32, i32, i32, i32, i32, i8*)
+
+; This test makes sure that such an access pattern is handled correctly
+; by PPCGCodeGeneration. It appears that not calling `preloadInvariantLoads`
+; was the main reason that caused this test case to crash.
+;
+; void f(int *arr, const int *control, const int *readarr) {
+;     for(int i = 0; i < 1000; i++) {
+;         int t = 0;
+;         if (*control > 3) {
+;             t += *readarr;
+;         }
+;         arr[i] = t;
+;     }
+; }
+
+
+target datalayout = "e-m:o-p:32:32-f64:32:64-f80:128-n8:16:32-S128"
+target triple = "i386-apple-macosx10.12.0"
+define void @f(i32* %arr, i32* %control, i32* %readarr) {
+entry:
+  br label %entry.split
+
+entry.split:                                      ; preds = %entry
+  br label %for.body
+
+for.body:                                         ; preds = %entry.split, %if.end
+  %i.01 = phi i32 [ 0, %entry.split ], [ %inc, %if.end ]
+  %tmp = load i32, i32* %control, align 4
+  %cmp1 = icmp sgt i32 %tmp, 3
+  br i1 %cmp1, label %if.then, label %if.end
+
+if.then:                                          ; preds = %for.body
+  %tmp1 = load i32, i32* %readarr, align 4
+  br label %if.end
+
+if.end:                                           ; preds = %if.then, %for.body
+  %t.0 = phi i32 [ %tmp1, %if.then ], [ 0, %for.body ]
+  %arrayidx = getelementptr inbounds i32, i32* %arr, i32 %i.01
+  store i32 %t.0, i32* %arrayidx, align 4
+  %inc = add nuw nsw i32 %i.01, 1
+  %exitcond = icmp eq i32 %inc, 1000
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:                                          ; preds = %if.end
+  ret void
+}