Fix off-by-one error in bucket sort.

The bad sorting caused a misaligned basic block when building 176.vpr in
ARM mode.

<rdar://problem/10594653>

llvm-svn: 146767

2 files changed, 27 insertions, 1 deletions

diff --git a/llvm/lib/Target/ARM/ARMConstantIslandPass.cpp b/llvm/lib/Target/ARM/ARMConstantIslandPass.cpp
index 7cdce3db163..2a7721bc74c 100644
--- a/llvm/lib/Target/ARM/ARMConstantIslandPass.cpp
+++ b/llvm/lib/Target/ARM/ARMConstantIslandPass.cpp
@@ -537,7 +537,7 @@ ARMConstantIslands::DoInitialPlacement(std::vector<MachineInstr*> &CPEMIs) {
 
     // Ensure that future entries with higher alignment get inserted before
     // CPEMI. This is bucket sort with iterators.
-    for (unsigned a = LogAlign + 1; a < MaxAlign; ++a)
+    for (unsigned a = LogAlign + 1; a <= MaxAlign; ++a)
       if (InsPoint[a] == InsAt)
         InsPoint[a] = CPEMI;
 
diff --git a/llvm/test/CodeGen/Thumb2/aligned-constants.ll b/llvm/test/CodeGen/Thumb2/aligned-constants.ll
new file mode 100644
index 00000000000..16b3a193c9d
--- /dev/null
+++ b/llvm/test/CodeGen/Thumb2/aligned-constants.ll
@@ -0,0 +1,26 @@
+; RUN: llc < %s -mcpu=cortex-a8 | FileCheck %s
+target datalayout = "e-p:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:32:64-v128:32:128-a0:0:32-n32-S32"
+target triple = "thumbv7-apple-ios"
+
+; The double in the constant pool is 8-byte aligned, forcing the function
+; alignment.
+; CHECK: .align 3
+; CHECK: func
+;
+; Constant pool with 8-byte entry before 4-byte entry:
+; CHECK: .align 3
+; CHECK: LCPI
+; CHECK:	.long	2370821947
+; CHECK:	.long	1080815255
+; CHECK: LCPI
+; CHECK:	.long	1123477881
+define void @func(float* nocapture %x, double* nocapture %y) nounwind ssp {
+entry:
+  %0 = load float* %x, align 4
+  %add = fadd float %0, 0x405EDD2F20000000
+  store float %add, float* %x, align 4
+  %1 = load double* %y, align 4
+  %add1 = fadd double %1, 2.234560e+02
+  store double %add1, double* %y, align 4
+  ret void
+}